The Lapco Slide Check allows users to remove a remote line without having to shut the main valve off. It allows for a quick disconnect without shutting the bottle valve off. Slide check to the rear to disconnect air source from marker. Slide check forward to allow air source to the marker. Slide check valve comes in Bead Blasted Billet Aluminum. The valve is equipped with the highest quality and most durable o-rings. Recently redesigned in June of '09, it offers top-notch consistent performance at a super price.