Description

Prusa Nextruder Silicone Sock — Set of 3

This is the OEM silicone sock set for the Prusa Nextruder — a heat-resistant silicone cover that fits over the heater block to protect it from filament buildup, oxidation, and heat loss. Comes as a set of 3, giving you spares for multiple socks changes without reordering.

Why Use a Silicone Sock

The heater block runs at high temperature and is exposed to stray filament ooze, blobs, and dust during printing. Over time this builds up on the bare metal surface, causing oxidation, stuck-on residue, and reduced heat efficiency. The silicone sock forms a protective barrier that keeps the heater block clean, prevents filament from adhering directly to the metal, and improves heat retention — resulting in more stable nozzle temperatures and reduced power draw to maintain temperature.

Improved Thermal Stability

By insulating the heater block from ambient airflow (particularly from the nearby part cooling fan), the silicone sock helps maintain more consistent nozzle temperature during printing. This is especially beneficial when printing with strong part cooling fan settings, where airflow can otherwise cause temperature fluctuations at the heater block.

Installation Safety Warning

Before installing, ensure the nozzle and heater block are completely clean. Never install the sock while the printer is running and hot — risk of burns. Allow the hotend to cool fully before handling.

When to Replace

Visible wear, tearing, or melting of the existing sock, sock has become brittle or lost its fit over the heater block, sock removed for cleaning and needs replacing, and as routine maintenance during hotend servicing.

What’s Included

Nextruder silicone sock × 3

Compatibility

Prusa MK3.9 / MK3.9S
Prusa MK4 / MK4S
Prusa XL
Prusa CORE One / CORE One+
Prusa CORE One L

Not compatible with the MK3/MK3S/MK3S+, MK3.5/MK3.5S, or Prusa MINI/MINI+.

Installation

Power off the printer and allow the hotend to cool completely before handling. Ensure the nozzle and heater block are clean before fitting the sock. Refer to the Prusa Knowledge Base repair manual for your specific printer model at help.prusa3d.com.