Full specification

Stainless steel base*
Plastic top (70% PC, 30% ABS)
Medical grade straight or tapered silicon strap
Dimensions: 37.5mm in diameter, 8.5mm in height
Weight: 34 g
Battery and power: Fully rechargeable lithium ion battery. Charges via a bespoke charging base in two hours
Waterproofing: Water and sweat resistant (IP65)

Tapered strap width: 16 mm wide, fits a wrist circumference between 12 cm - 20 cm

Straight strap width: 20 mm wide,  fits a wrist circumference between 12 cm - 21 cm

*doppel’s stainless steel metal base contains very small quantities of nickel, however, the amount falls below the strict nickel restrictions set by European REACH regulation. Therefore, while nickel exposure is unlikely to be a problem, you should be aware of the possibility in case you're susceptible to nickel-related reactions.