Wolff solid recoil guide rods for the Springfield 4" XD Series pistols allows the use of Wolff recoil springs in various weights to allow tuning of the recoil function. Wolff XD(solid guide rods are a precision, hi-quality one piece steel quide rod. Designed for optimum performance they replace the standard factory recoil system. Rods are hardened to a minimum RC-55 for durability. Available in a durable black finish. Available individually or with a Wolff recoil spring.