The ROOK Tactical Gen 4 to Gen 3 Guide Rod Adaptor allows you to utilize the GLOCK Generation 3 springs in a GLOCK Generation 4 slide. Available in Stainless Steel, Titanium Nitride (TiN) and Diamond Like Carbon (DLC) the Adapter solves problems of sourcing parts or allows you to use a preferred guide rod setup or uncaptued spring. 
 
Pairs well with the ROOK Tactical Smoother Operator Guide rod alloweing its use in Generation 4 Pistols.