Denudation and Handling Pipettes

Denudation and Handling Pipettes 2

The Stripper™ and EZ-Range™ denuding and handling devices are designed to carefully transfer oocytes and embryos throughout the in vitro fertilization (IVF) pathway from oocyte retrieval, when COCs enter the lab, until the embryo is placed in the embryo transfer dish.

This product is available for sale in selected countries worldwide.

The combination of our EZ-Range and The Stripper family presents an extensive, customizable variety of tip sizes and pipettors that will suit your preferences. This variability ensures that the pipettes can be seamlessly adapted to accommodate the unique demands of various IVF protocols.

The use of The Stripper Tips or EZ-Tip™ Pipette Tips for denudation of the oocyte helps to minimize the duration of exposure to additional chemicals such as the hyaluronidase enzyme.2

These pipettes are designed to meet the diverse requirements of both clinical and research laboratories.

  • Proven: Tried and tested for decades
  • Durable: Robust plastic tips
  • Soft: denudation and handling tips are fire-polished to minimize scratching of plastic1
  • Versatile: All size options available for denudation and handling
  • Compatible: Tips are designed to industry standards and compatible with pipettors accepting 0.9mm tips

Our close-tolerance plastic tips are flexible, featuring smooth edges and consistent geometries for precise laboratory work. Crafted from medical-grade plastic, these tips ensure durability while preventing scratches on delicate surfaces such as Petri dishes.


All our tips are:

  • For IVF use: Sterilized in accordance with the ISO 11137 standards for gamma irradiation, mouse embryo assay (MEA) and Limulus amoebocyte lysate (LAL) tested
  • Available in all sizes necessary for oocyte denudation, manipulation, and transfer of embryos or COCs, as well as for PGT biopsy work
  • Premium quality tips with consistent geometries and close-tolerance diameters ranging from 75µm-600µm with smooth edges
  • Three-year shelf life
  • Designed to be flexible and will not scratch plastic ware
  • The 0.9mm proximal outer diameter fits The Stripper pipettor and is compatible with all standard denudation and transfer IVF pipettors
  • Multipack tips for convenience and economy
  • Individually packed sterilized tips
  • Color coded for easy identification

Our tips provide both convenience and economic efficiency, making them an essential tool for laboratories seeking precision and reliability in scientific applications.

Maybe your hand is on the small side and a thin pipettor fits best, or you value a pipettor that can be sterilized by autoclaving? Make sure you read about and test both our classic pipettor families:


EZ-Squeeze™ Tips and EZ-Squeeze™ Handle: ease of handling
and a comfortable working position.


EZ-Strip™ single-use denudation and handling system: has been developed for meeting laboratory sterility standards, minimizing risk of cross-contamination.2

Classic tips for pipettorsBulb pipetting range
Size in µmUsageThe Stripper Tips
both vials of 20 or single packed
single packed
vial of 20
pack of 20
pack of 20
50HandlingThe Stripper PGD only
100Handling of biopsiesX
175Denudation and HandlingX
1000HandlingThe Stripper CC only

A large denudation pipette is suggested to move the COC in enzyme and for the initial pipetting to loosen the cumulus cells.

Following the enzymatic reaction, a series of pipette tips with decreasing size, from 175 to 150µm can be used. This will force the remaining corona radiata cells to fall off the surface of the oocytes, hence the name “stripping.”3

The oocyte should be subsequently washed in HEPES and/or MOPS buffered handling medium by transferring between several wells to remove all traces of the enzyme.

The size of the pipette chosen, should be small enough to carefully remove the cumulus cells surrounding the oocyte without causing damage to the egg itself. ASRM3 recommends using pipette tips with decreasing size, from 175µm, to 150µm and 135µm internal diameter for oocyte denudation best practice.

Tip diameters of 100 µm and smaller can be used for handling biopsied material for PGT or smaller species’ oocytes, e.g. mouse. Tip diameters of 125-175µm can be used for oocyte handling. Tip diameters of 200-300µm can be used for specimen handling, such as blastocysts, expanded and zona-free blastocysts. A larger diameter is also advised when handling biopsied embryos and blastocysts. Tip diameters of 600-1000µm can be used for handling larger cell masses like COCs.

The Stripper PGD pipettor and the 50µm accompanying tips are designed for handling and tubing biopsy material. The 75µm EZ-Tip and The Stripper Tip can also be used for this purpose.

The sizes from 170-180µm are most suitable for handling cleavage stage embryos.

The sizes from 200-300µm are most suitable for handling blastocysts and expanded blastocysts.

We recommend using The Stripper CC and The Stripper CC tips which are 1000 µm in inner diameter.

Our pipette tips are made of medical-grade plastic which will flex and not damage the Petri dish.

IVF-certified plastics are specifically designed and tested to be safe for use in medical procedures, including IVF treatments. These plastics undergo rigorous testing to ensure that they are free from toxic substances and contaminants that could potentially harm embryos or compromise the success of the IVF procedure.

All EZ-Tip and The Stripper tips are compatible with commonly-used denudation pipettors with a 0.9mm outer diameter.


  1. Naji, O., Moska, N., Dajani, Y., El-Shirif, A., El-Ashkar, H., Hosni, M.M., Khalil, M., Khalaf, Y., Bolton, V. and El-Toukhy, T., 2018. Early oocyte denudation does not compromise ICSI cycle outcome: a large retrospective cohort study. Reproductive biomedicine online, 37(1), pp.18-24.
  2. CooperSurgical data on file.
  3. ASRM oocyte denudation best practice
ProductOrder Code
EZ-Grip® without Comfort Rest7-72-2800
EZ-Grip® with Comfort Rest7-72-2802
EZ-Grip® Spares Kit (1x replacement seals / 1x M2.5 hexagon key / 1x plunger wire)5-72-2000
EZ-Range Stand6-72-2810
Nominal SizeUsageColour1 x vial of 20 code(20 pipettes)5 x vial of 20 code(100 pipettes)Singles Code(20 pipettes)
Nominal SizeUsageColourPack of 20 Order Codes
145µm LongHandling in tubesWhite7-72-3145L/20
EZ-Squeeze™ Handle fits all sizes in the EZ-Squeeze™ range7-72-3002
Nominal SizeUsageColourProduct Code for 20 Individually packed EZ-Strip
145µm LongHandling in tubesWhite7-72-1145L/20
ProductOrder Code
The STRIPPER® MicropipetterMXL3-STR
The STRIPPER® Micropipetter with Free Standing Comfort GripMXL3-STR-CGR
The STRIPPER® Plunger ReplacementMXL3-PLG
The STRIPPER® Repair Kit (includes O-rings, Spacer, Collett)MXL3-ORK
The STRIPPER® Comfort GripMXL3-CGR
ProductColourOrder Code
Tips – 50μm (20/pk, individually packaged)Pea GreenMXL3-IND-50
Tips – 75μm (20/pk, individually packaged)TealMXL3-IND-75
Tips – 100μm (20/pk, individually packaged)Dark GrayMXL3-IND-100
Tips – 125μm (20/pk, individually packaged)BlueMXL3-IND-125
Tips – 135μm (20/pk, individually packaged)YellowMXL3-IND-135
Tips – 150μm (20/pk, individually packaged)BlackMXL3-IND-150
Tips – 175μm (20/pk, individually packaged)RedMXL3-IND-175
Tips – 200μm (20/pk, individually packaged)BurgundyMXL3-IND-200
Tips – 275μm (20/pk, individually packaged)Hunter GreenMXL3-IND-275
Tips – 600μm (20/pk, individually packaged)Light GrayMXL3-IND-600
Tips – 1000μm (20/pk, individually packaged)WhiteMXL3-IND-CC
ProductColourOrder Code
The STRIPPER® CC MicropipetterMXL3-STR-CC
The Stripper CC Tips -1000μm (1 vial with 20 pcs)WhiteMXL3-CC
The Stripper CC Tips – 1000μm (20 individually packaged tips)WhiteMXL3-IND-CC
ProductColourOrder Code
The STRIPPER® PGD Micropipetter with Comfort GripMXL3-STR-PGD-CG
Tips – 50µm (1 vial with 20 pcs)Pea GreenMXL3-50
Tips – 50μm (20 individually packaged tips)Pea GreenMXL3-IND-50
The STRIPPER® PGD Plunger ReplacementMXL3-PLG-PGD
The Stripper Comfort Grip, which can also be assembled onto The Stripper PGDMXL3-CGR

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The pipette is made of medical grade plastic, which will flex and not damage the Petri dish

We have tested EZ-Tip® with the commonly-used denudation pipettors with a 0.9 outer diameter. EZ-Tip® is intended as a high quality replacement for other brands.

EZ-Tip® pipette tips and all popular pipette tips with a 0.9mm outer diameter.

The EZ-Grip® may eventually require a replacement plunger wire and ‘O’ rings after extended use. These can be ordered from RI. One set is supplied with the unit.

Supplied with the EZ-Grip®is a M2.5 hex key tool that is needed to loosen and replace the plunger wire. No tools are required to replace the seal.

We believe we use higher quality component parts to minimise maintenance requirements.

It is compatible with handles with a 4mm inner diameter. However, a EZ-Squeeze™ handle is supplied as required.

It is compatible with pipettes with a 1.5mm outer diameter with a bulb with a 4mm outer diameter.

As a single-use system, EZ-Strip® minimises the risk of cross-contamination, which is of paramount importance in assisted reproduction.

RI has an environmental policy and it limits waste as much as possible. Clinics may consider that the benefits of minimising the risk of cross-contamination outweigh environmental concerns of additional packaging of a single-use item.

The pipette is made of medical grade plastic, which will flex and not damage the Petri dish.

Once a multipack is opened the sterility of each unit is compromised. With individual packaging, the sterility of each EZ-Strip® is guaranteed.



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Get In Touch With Us

We’d love to hear from you. How can we help?