Spuhr Chassis Weight Kit Interior 2-Pack. The highly modular chassis shares the same proprietary Spuhr Interface system as the Spuhr Ideal Scope Mount System (ISMS). The interface consists of circular grooves and ridges surrounding M4 screw holes which allows ISMS accessories to be installed on the SICS chassis. Specifications for Spuhr Chassis Weight Kit Interior: Manufacturer: Spuhr Weight: 340 g Features of Spuhr Chassis Weight Kit Interior Angled groves to provide texture Package Contents: Spuhr Chassis Weight Kit Interior Spuhr CA004: Chassis Weight Kit Interior 2-Pack