Straight Tongue Couplers Like all Atwood couplers, Straight Tongue Couplers are manufactured in the U.S.A. and offer high quality, secure latching for S.A.E. class 2, 3 and 4 rated trailers. They are die formed from heavy gauge steel for added durability and strength. Atwood straight-tongue couplers are designed for a variety of applications that include bolt-on for 3" channel, weld-on for 2" and 3" channels and weld between use.