only place I found that part number is here but the specs are slightly different. lowes looked at me like I was nuts.
http://www.ebay.com/itm/Free-Ship-10-Count-Lot-Hillman-07828-3-4-x-2-3-16-x-105-Spring-Extensions-/141589342970?pt=LH_DefaultDomain_0&hash=item20f761eafa