Im not an engineer and consider that to be dear compared to what I paid for my trigger ring.
when you can get them laser cut from 5mm steel for 20-25 quid from many sites including : http://trigger-wheels.com/
I think it is expensive by comparison. Although I would like a nice shiney or fancy looking trigger wheel the fact that it costs so much simply puts me off.

even with 50% discount 70 quid its a bit rich for my liking as you can get a lazer cut steel one for less than half that price.