HO-Scale Knuckle Springs For all Standard Head Couplers. (Except #58, #78, #119, #150-Series, #178, #711, #714, & #2100) One dozen per package WARNING: CHOKING HAZARD - Small Parts - Not for children under 14 years. Kadee? Quality Products Co. products are not toys and are not intended for children under 14 years old.