I know what you are talking about now!! I am a bit slow sometimes
Slide Locks
http://www.boatersworld.com/product/329511117.htm
Sliders
http://www.boatersworld.com/product/167100056.htm
Bimini Top Slide Track Assemblies provide an easy way to slide your bimini to and from a storage position. Each Slide Track Assembly Kit includes two lengths of slide track, four end caps, two track stops, stainless steel mounting screws, and two slider mounts for deck/gunnel mounting or two slider mounts for side mounting
also:
http://www.boatersworld.com/product/329512578msk.htm