However, the new law did not apply to modelgun made in plastics and so it also stimulated the production of more plastic modelguns by various manufacturers. The modelgun makers imposed some voluntary industrial restraints (self-regulation) to the plastic modelguns to prevent modification and for easy identification as modelgun. It requires the insert of a piece of hardened steel plate (called spacer) inside and across the barrel and this insert must be visible from the muzzle. Also, the front of cylinder chamber of revolvers must be blocked (fully or partially) by metal barrier too. Thereafter the ASGK manage the safety approval and SPG (Safe Plastic Gun) mark started to appear on the plastic modelguns to indicate the conformance to the regulation. But Marushin withdrew from ASGK in 2007 and coordinated to launch the All Japan Toy Gun Safety Association (STGA)(全日本トイガン安全協会). Since then, the STGA mark appears on Marushin and Tanio Koba products for similar safety indication. KSC, Hudson and Kokusai also left ASGK and joined the Japan Air Sports Gun Association (JASG)(日本エアースポーツガン協会) in 2000s and JASG safety mark may appear on some of their newer products. However, some modelguns may not show any of the safety mark on the frame, but just have safety label affixed on the packing.