Available in a 3.5mm, 4.0mm and the NEW 5.0mm stroke version 3.5 stroke - Our gentle version. Small to medium lines. Perfect for black and grey and soft colour blending 4.0 stroke - Our most versatile version. Small to large lines with ease. Excellent colour blending and effortless packing 5.0 stroke - Our strongest version. This machine has a sharp, hard hit. Medium to large lines like a laser! Effortless packing and single pass colour saturation Brushed, coreless motor Internal fixed 1800 mah lithium ion battery Fast charging USB-C port Straightforward digital voltage display Travel case and charging cable include NEW Autoclavable 36mm, 38mm and 48mm Stainless Steel grips available here Comes with a 35mm anodized sterilizable aluminium grip Disposable 38mm and 48mm grips sold separately here Refer to the included manual for detailed usage and set up instructions If the 2 batteries are not enough, spare batteries are available GOOD PEN BATTERY. UPDATED AND IMPROVED 4 programmable voltage preset Boost mode for hard starts and stiff membrane cartridges (quick press the power battery twice) 6 month warranty on all batteries Compatible with all 3 wireless models This battery is only compatible with the GOOD PEN Wireless system We strongly recommend you regularly run your battery to zero charge for longevity of the battery Thank you for your trust and support!