Expansion Rv plugs seal cross-drilled construction holes. Installation is easy with pneumatically powered rivet gun that pulls a tapered mandrel through a sleeve to create an expansion seal. Standard and long mandrel varieties come in metric sizes from 4 to 10 mm. Sleeves come in carbon steel and black oxide; mandrel comes in corrosion-resistant lubricated carbon steel. Farmington Engineering, (203) 245-1100, www.farmingtoneng.com