Vinyl Works SLA-T Model SLA Slide-Lock A-Frame Ladder, this premium a-frame ladder has a rigid frame design to eliminate racking and an extra tread for easy climbing. It is adjustable from 48” to 56”. This a-frame ladder features a “slide-lock” design. The exterior ladder section can slide up and can be locked to form an additional entry barrier for greater security (lock not included). It also includes an anti- entrapment barrier.