For maximum performance we recommend 90 PSI air pressure905146 — Standard Spring Retainer — Bulk - fits 404123 (AH150M), 404124 (AH150L), 404126 (AH150SD) and 409131 (RH954) 408291 — Quick Coupler Retainer - Fits 404123 (AH150M), 404124 (AH150L), 404126 (AH150SD) and 409131 (RH954) 408292 — Standard Spring Retainer — Carded - Fits 404123 (AH150M), 404124 (AH150L), 404126 (AH150SD) and 409131 (RH954) 905852 — Beehive Retainer - Fits 404123 (AH150M), 404124 (AH150L), 404126 (AH150SD) and 409131 (RH954) 905861 — Standard Spring Retainer for 0.498 Steel Bits - Fits 409132 (RH955) 905862 — Beehive Spring Retainer for 0.498 Steel Bit - Fits 409132 (RH955)