'Colson' is a particular brand of 'rilsan' or cable tie, though unfortuantel, I suspect it is highly likely here that they are just using it in the generic sense [like hoover for vacuum cleaner], as it is very commonly used that way; I think you'd be safe to assume that, unless they make a habit of quoting specific-brand products elsewhere

col. = abbreviation of 'collier', the proper (non-proprietary) name for a cable tie

As your long. has a period/full-stop afte it, it may be short for longeur = length... followed by a dimension (in mm, I'd expect) --- these things come in all sorts of lengths, commonly between 100mm / 4" and 500 mm / 20" or more...