勾扳手又稱月牙形扳手，俗稱勾扳子，用于擰轉厚度受限制的扁螺母等；于拆裝車輛，機械設備上的圓螺母，卡槽分為長方形卡槽和圓形卡槽。制作工藝：使用   合金鋼經高溫鍛打而成，，.適用圓螺母的外徑范圍:S:22~26S:28~32S:34~36S:38~42S:45~52S:55~62S:68~72S:78~85S:90~95S:100~110S:115~130S:135~145S:150~160S:165~170S:180~200S:200~220S:240~260S:260~280S:280~300S:300~320S:320~350S:360~380S:380~400S:400~420。