Truck Upfitters Premium Gas Struts for Snuglid Fiberglass tonneau covers. Compatible with most Snuglid SL and F2 Models for compact and fullsize truck with extrashort and short beds (5.5-6.5' long). These ARE NOT COMPATIBLE WITH ALL Snuglid fiberglass tonneau. Please measure your existing struts before replacing with these. These are 80 lb struts, so they are compatible with heavy weight fiberglass Snuglid and other similar brand tonneaus that have 2 single lift style arms. Please check out our other sizes and pressures of gas struts by searching for Truck Upfitters. NOTE: These struts require two people to install, one person to held cover in open position while another removes and replaces the strut. Removing strut while cover is open and unsupported can cause injury or damage.