Twist-o-flex are the classic old style stretch metal bands. Twist-O-Flex Metal Expansion 42mm / 44mm Stainless Steel Stretch Watchband Replacement for Apple Watch Series 1, 2, 3, 4 and 5 in Brushed, Silver and Black by Speidel https://www.amazon.com/dp/B075KHFCBJ/ref=cm_sw_r_cp_api_i_Wl0xFbD8F1P3S