I've been using the 11:1 silver sparks for over a year now in a few bots. The pair I'm currently using has lasted nearly 20 matches in addition to a good deal of practice. They're fantastic gearboxes if you need small wheels and a lot of speed.

I had purchased two of these motors recently to upgrade my Fingertech Viper MKII. One of the motors works great, but the other already has a stripped gearbox after less than a minute of runtime. These motors are powerful for their size and very sturdy, but it seems that Fingertech's quality control is less than stellar.