The Whoop strap with the very accurate Amazfit sensor offers you the same Whoop features without the need to pay an annual subscription. A special adapter has been designed to be installed on Whoop straps, meaning the watch is not a regular Amazfit Helio, and please keep this in mind. The watch cost me about 1500 SAR, from the price of the Helio to designing and printing the adapter with a 3D printer, and buying a Whoop strap. In short, the strap from the outside looks exactly like the Whoop and gives you the same features without the need for a subscription.