Air Displacement Puck

⚠️ Please measure your cylinder's inner diameter before ordering — see the compatibility table below. ⚠️

What it does

The puck fills the unused air space above your glans in the cylinder. Less empty volume means faster pressure transitions - there's simply less air to move to reach your target vacuum. It makes a real difference for Milking and RIP, especially with a manual or slower electric pump, and it's most noticeable in larger cylinders with a lot of dead space. 

Why this one is different

Inspired by Karl's original displacement puck concept, the PEMods Puck takes the idea further with a fully modular, magnetic system.

• Magnetic - no O-rings. Pucks hold to each other via embedded neodymium magnets. They don't seal (there's a central air channel for airflow), they just hold the stack together and keep it in place.

• Foolproof stacking. The magnet layout means the pucks only stack the right way, so you can't get it wrong. No dedicated top piece needed.

• Easy to remove. Two magnets sit on top of the cylinder and hold the whole stack in place. Take them off and the stack drops right out — no fishing around with a rod, no hook inside the cylinder.

• Easy to clean. No O-rings means nothing that traps fluid or wears out over time — just pull the stack apart, rinse, done.

• Labeled. Each puck is printed in black with its size marked in white, so you always know what you've got.

How many pucks do I need?

Measure the empty space above your glans at working length - that's the dead volume you want to fill. Stack pucks to take up most of it, but leave around 1 cm / 0.4" of clearance at the top so you're not pressing directly against the stack. Combine 25 mm and 10 mm pucks to fine-tune the height, and include at least one 10 mm puck so you can adjust in small increments.

Minimum order: 3 pucks
€13.90 per puck
€11.90 per puck on orders of 6 or more

Compatibility & Sizing:

Cylinder Size / Inner Diameter / Puck Diameter

2.50 / 61.2mm / 60.5mm
2.24 / 54.9mm / 54.2mm
2.125 / 52.0mm / 51.3mm
2.00 / 49.0mm / 48.3mm
1.85 / 45.3mm / 44.6mm
1.73 / 42.4mm / 41.7mm
Valve (all sizes) / 10.0 mm

Every manufacturer uses different tolerances and inner dimensions. The values above are reference measurements only - fit is not guaranteed. Whether a puck fits also depends on factors such as flange design and internal geometry, which vary between cylinders of the same nominal size.

Shipping: Europe only. Orders outside Europe cannot be fulfilled at this time.

If your cylinder is not listed, or if a puck does not fit despite matching the listed size, please contact us. Custom sizes are available on request. (Custom orders are non-refundable).

Material: PLA
Colour: Black
All pucks may have slight dimensional variations of ±0.5 mm. This is inherent to the manufacturing process and does not affect functionality.