The Halcyon Cinch Quick-adjust system may be used with a single or double tank configuration. When in use with doubles, the lower part of the Cinch adapter plate features molded spacers to keep the harness webbing from being pinched by the tanks; this ensures the webbing can slide freely. In most cases the lower bolt of your double tanks will be of sufficient length to allow this slight offset. However, the Halcyon bolt extender allows divers to extend a short lower bolt where necessary. The bolt extender threads directly to the lower bolt of a double tank configuration; it uses an inset Allen key fitting so it can be easily tightened in place.