ACDelco 510-991 Professional Convertible Top Stowage Cover Lift Support Superior seals keep lift support fluids and gases contained within the strut components, resulting in extended product life Chromed rod increases rust and corrosion resistance for a higher quality, longer lasting, lift support Rubber O-ring piston seal for controlled lift Heavy gauge steel pressure tube provides long life Polytetrafluroethylene (PTFE) backup ring gives enhanced performance