"This module lacks a cable tie and the clips pinch the wires as you use the insertion tool. The lack of a cable tie means you won't want to disturb this after installation, too. Not clever design at all. If you are fitting a lot of these, you will definitely want to look elsewhere."
"I bought these some time ago and needed one to finish a job.
Reason 1) - marked up with the A/B schemes - no-one uses A from new now, so just adds to the confusion
Reason 2) - totally unreliable. Mating these with TE Connectivity (good plugs) RJ45 and 4 out of 8 ways would not test out. After much time-wasting, traced the fault to sloppiness in plug to socket mating. RJ45 is RJ45 so all brands should interconnect.
Installed many sockets, patch plugs and never had this problem. I could recommend a good modular socket, but Screwfix wouldn't like it.