These are HellermannTyton Insulok T50I cable ties in black, sold as a pack of 100. The T50I is a medium-length, medium-width tie from HellermannTyton's T-Series: about 300 mm long (the supplier lists 305 mm) and 4.6-4.7 mm wide, with inside serrations and a one-piece plastic pawl that locks the strap as it is pulled through the head. It bundles from about 1.5 mm up to 85 mm diameter, which makes it a good general-purpose size for dressing cable runs behind equipment racks, in flight cases and stage trunking, and for bundling microphone, speaker, DMX and power leads. HellermannTyton's head dimensions for the T50I are 7.0 mm long by 7.8 mm wide. The supplier describes this particular version as black polypropylene; HellermannTyton's standard T50I is polyamide 6.6, so the exact material and its tensile rating should be treated as per the supplier's listing. The ties apply quickly by hand thanks to the bent tail and can also be fitted with HellermannTyton tensioning tools. They are single-use, non-releasable ties, black in colour.