Johnson' Handy Lock 01 Series stainless steel turnbuckle has all of the features for easy adjustment. It is neat, compact, and positively locked without cotter pins or check nuts. There are no sharp points to catch lines or tear sails, just flip the lever up to adjust and down to lock. The 115C is the Jaw & Swage model and is calibrated. It is designed for 5/32 in. (4mm) wire and 1/4 in. (6mm) thread size.
Johnson recommends that working loads not exceed 40% of the approximated breaking strength.