Nitto No.21 (Type 21) is a general-purpose PVC electrical insulation tape made by Nitto Denko, supplied in South Africa through HellermannTyton, and this listing is the yellow roll: 0.2 mm thick, 18 mm wide and 20 m long. Electricians, sound and lighting crews and installers use it to insulate and protect cable joints and repairs, bundle and tidy wiring, seal the ends of cable looms, and colour-code conductors, circuits and cable lengths so they can be identified at a glance. Yellow is commonly used for phase identification, marking a particular circuit, or flagging cables that need attention. HellermannTyton's South African listing rates the tape for -10 to +80 degrees C and gives an adhesion of 1.8 N/cm, tensile strength of 26 N/cm, 200 per cent elongation and a breakdown voltage of 9 kV. It is described as cold and weather resistant, unaffected by moisture and most chemicals, with good ageing characteristics and no flagging (unwinding at the ends) even under high temperatures. Nitto's own product information describes No.21 as a lead-free vinyl tape that tears easily by hand and has strong initial adhesion. Other colours are listed separately.