I have thus punched the Micro-Sim (large chip and with beliegenden adapter) to the size of the Nano-Sim. It has at least works, but it has a lot of play when inserting and especially with SIM cards in which the chip is the same size as a nano-Sim, you have to be extremely careful that the SIM is exactly in the device. The adapter does not fit exactly, so I had my SIM card smaller arrows before. I am glad that it worked, but I think with trimming one is, at least for large chips on the safer side. Despite metal I would not use the device too often.
