Fimmers plays left-handed and has used 5-string as well as 6-string bass guitars. He is noted for his extremely fast left-hand technique and extended use of tapping as well as occasionally playing bass solos. He plays all the songs with fingers, although he does not apply the slapping and plucking technique. Most of the time he uses three fingers to get the speed. He starts with the index finger at the three finger technique, what is in his opinion very comfortable.
Fimmers keeps it simple as far as his equipment goes: he uses an Ampeg SVT4 Pro and SWR 750x bass amplifier heads through 8x10" SWR cabinet, along with a Blue Thunder preamp for compression. Earlier in his career, he was using a 6-string bass from the German custom manufacturer Eyb, but has changed to a 6-string Vigier since.