Threaded caps that effectively protect external threads where, in most cases, the liquid is inside the application that is tested under pressure. Some products are available with sealing to ensure tight closure. Soft and hard material versions are possible in order to match different requirements. Shape with outside vertical ribs to ease fitting and removal with a tool. They are recommended for several applications: cylinder blocks, cylinder heads, adapter plates, connecting rods, lubrication pumps, balance units, oil sumps, timing gears. In this range some parts are available with washer or O-ring.