Unlike Schering's Testoviron Depot the Primo amps don't come supplied with a file. But below the blue dot there's a score line for breaking the amp. I found that these glass amps were a little bit too brittle and inclined to break if I did'nt score the line deeper still with a old file. Something to remember with these.
'KeyLow' if you need me to take anymore for you just ask, it's no problem with the digi-camera.
Regards
Bouncer