Compatible Devices:-Fitbit Alta 2016-Fitbit Alta HR 2017-Fitbit Ace 201810 pack-a combination is the SNAP TYPE BUCKLE DESIGN for Fitbit Alta Bands/Fitbit Alta HR Bands/Fitbit Ace Bands.10 pack-b and 10PCS-C combination is the classic WATCH BUCKLE TYPE DESIGN for Fitbit Alta Bands/Fitbit Alta HR Bands/Fitbit Ace Bands.Colors of 10 pack-a are Black, Blush pink, Purple, Navy blue, Slate, White, Rose pink, Orange, Green, Teal Colors of 10 pack-b areNavy blue, Black, Brown, Fuchsia, Grey, Teal, Orange, Blush pink, Lilac, WhiteColors of 10PCS-C areRose gold, Gold, Silver, White, Blush pink, Black, Navy blue, Grey, Fuchsia, TealDimension and Size: - Small size fits for 5.5inch-8inch/140mm-203mm wrist- Large size fits for 6.7inch-8.7inch/170mm-221mm wristPackage Content:- 10 pieces Fitbit Alta straps or Fitbit Alta hr straps or Fitbit Ace straps- NOTE: What you get is ONLY Fitbit Alta WRISTBANDS or Fitbit Alta hr wristbands or Fitbit Ace wristbands, NOT ANY OTHER accessories INCLUDED.How to Contact AK-USA-STORE:1. Find "AK-USA-STORE" in this Page→Click "AK-USA-STORE"→Click "Ask a Question"→Send Questions with your Order Number or the ASIN of the product to AK-USA-STORE2. Go to your Order Page→Find your Order Number→Click "Get Help with Order"→Send Questions to AK-USA-STORE, we will give you a fast reply within 12 hours.Explore More:-Search "AK Bands" for more bands offered by AK-USA-STORE.After-sale service:- If the Alta bands/ Alta HR bands/Ace bands have any problem, please feel free to contact us via e-mail - Quick Response within 12 hours.