Straffr

STRAFFR is much more than just a fitness band. Since it has a sensor integrated directly into the band that measures its performance during training. Straffr has a smartphone app that connects to the band via Bluetooth in real time! Measuring force exerted, repetitions, training duration and more!
STRAFFR training is for beginners and advanced alike, and there are two distinct bands:

BLUE STRAFFR  

Medium with 5-15 kg                
          or  
RED STRAFFR

Strong with15-25 kg.