URBEST Digital PH Meter, Black 3: 1 ratio | 117 pieces | 3.5Lengths | thin adhesive inside liner 6 sizes: 3/32(40 pcs), 1/8(30 pcs), 3/16(20 pcs), 1/4(15 pcs), 3/8(6 pcs), 1/2(6 pcs) This product has a 3: 1 shrink ratio and is both ul & csa certified for up to 600V @125 degree centig.Product is also rohs compliant Dual wall | color: Black Comes with storage box