Caster : A pivoting wheel, containing a wheel lock, a swivel or non-swivel lock or both, which is attached to the base of a scaffold tower for manual movement of the scaffold; a caster does not have to contain a swivel
Spider, A Division of Safeworks, Glossary of Powered Access & Safety Terms, WA 98188, USA 2004. www.spiderstaging.com, http://www.spiderstaging.com/PDF%20Files/Catalog/A ppendix%20-%20Glossary%20of%20Powered%20Access%20S afety%20Terms.pdf, (Pwr Suspended Access Safeworks in Spiderstaging and Spiderbasket Usage - Amer) {466}