STATIMAT 4U is an automatic tensile- and linear-density tester for very coarse and high-tenacity yarns with a force measuring range up to 5.000 N. Special features like heavy-duty clamps with automatically operated force reduction cams and a rotary clamp to apply a twist to the yarn prior to tensile testing make the STATIMAT 4U unique in the field of automatic tensile testing of threads. STATIMAT 4U is suitable to test even Aramid and high-tenacity Polyethylene (UHMWPE) yarns. A further application is twist-testing of threads.