1, casing safety clamp 2, to connecting test string and swing square 3, pipe diameter from 1-1/8" to 4-1/2" available Safety clamp Type: WA-T used in connecting test string and swing square. Range(inches)Part No.Links ReqdWeightLbs.kg1-1/8~2QSSF0243616.32-1/8~3-1/4QSSF0254018.23-1/2~4-1/2QSSF0264420