It's a question of time. Wait some months using the mouse up than 12 daily hours and your muscles will be sufficiently hard to support it. The only trouble is an arm bigger than the other one

It's my case ;)

Ps. It isn't a joke. Usually I use Poser up than 12 hours in a day. But I work profesionally with it

CASETTE
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"Poser isn't a SOFTWARE... it's a RELIGION!"