DeWalt N394408 Spare Part - O RING

Genuine DeWalt N394408 O‑ring — a black elastomer sealing ring (commonly listed at 17 x 3 mm) engineered to restore the grease/air seal in the piston/chamber area of DeWalt rotary hammers.

This small but critical seal stops grease loss and keeps dust and moisture out of the hammer mechanism, helping recover consistent impact performance and preventing premature wear of internal parts.

Fits a range of DeWalt rotary-hammer models, including D25333K and D25334K series and many DCH/DG-series hammers such as DCH283, DCH293, DCH323, DCH333 and DCH334 (compatibility confirmed in parts listings).

If you keep spare DeWalt spare parts for maintenance, this N394408 O‑ring is an inexpensive, direct replacement to get a worn hammer back to spec without a major rebuild. Use basic hand tools to remove the old ring and press the replacement into the groove—being careful to seat it evenly to avoid pinching.

Order this original DeWalt sealing ring when a leaking or low‑impact rotary hammer needs a targeted repair rather than a full parts overhaul — it’s one of the small power tool parts that makes a big difference in reliability.