The optional neck extension for gerry the giraffe has been designed to use with a swinging cribs only this neck extension uses velcro and attaches between gerrys body and head making the sleepybobo long enough to reach the standard heights of swinging cribs inside gerrys neck hidden by a strip of velcro is the unique adjustable strap that allows you to adjust the neck to fit your crib there is also a flip out stability base that can be used to weigh gerry down all patent pending