These aren't very large at all. Not much bigger than a soldered pigtail with heat shrink tubing unless you are working in very tight places, have a lot of splices to do, or are using them for HO or N Gauge.
Length is 15mm, narrow part is 6mm wide, round part diameter is 10mm. Suitable for 19 - 26 Gauge wire. Encased in silicone the connection should be just as good as a soldered one in heat shrink tubing.
Yes you have to cut it off if you need to remove the wire just like a soldered one. They are not a lever connector like a Wago, but they aren't nearly as big as those either. When I used it I used a temporary wire nut to test it before crimping this on.
John
