When you perceive airflow at the top of the nail gun you are using, and there is also a slight sound when shaking, these problems make us suspect that there is a problem with the internal structure of the nail gun. The most likely situation is that the nail gun head valve is broken. A head valve that can be used for a long time is undoubtedly the best part to repair the symptoms of nail guns. As for its perfect replacement, we first recommend the 180450-s head valve. Why did you choose it? The 180450-s head valve kit is forged from high-density plastic material and has the strictest sealing performance. When used in conjunction with its O-ring and small metal washer, its effectiveness will be maximized. 180450-s has high compatibility and is compatible with the following nail gun models:DWFP12231 (Type 0)、DWFP12232 (Type 0)、DWFP12233 (Type 1) DWFP1838 (Type 1)、DWLHF2025K (Type 0) DWEHF1838K (Type 0)、BN200C (Type 1)、NS150C (Type 1)、BN200SB (Type 1)、SB-2IN1、SB-1850BN、SB-1842BN、SB-150SX、SB-100SX、SB1850BN、SB1850BN、SB-125BN、SB-2IN1、SB-2IN1、SB-1842BN、SB-150SX、SB-100SX、BT1855、SX1838、SX1838、SL1838BC、BT1855K、SX1838K、EHF1838K、LHF2025K、BTFP12233、BTFP1850K、SWK1850BN、BTFP12233 (20003001 AND HIGHER). SL1838BC (161200001 > higher) BT1855K (12340000 and Higher) SL1838BC (151230000 > higher) BT1855K (10152000 and Higher) BTFP12233 (15150000 and higher) SB-1850BN (17179001) LHF2025K (161200001 and higher) EHF1838K (161200001 and higher) SB-1850BN (14065000 and Higher) The above models are not all listed. Please confirm the compatible model of your device before placing an order. Thank you. 180450-S Head Valve Fits for Replacement Bostitch 180450-S Nailer Head Valve Body 7179001 0152000 BN200C BN200SB BN200SB BT1855K BT1855K (4Pcs)