Our Smart Cables are designed to be compatible with Apple Watch Series 3 (38mm case), Series SE/4/5/6 (40mm case), and Series 7/8 (41mm case). In addition, we have other models available for Series 3 (42mm case), Series SE/4/5/6 (44mm case) and Series 7/8 (45mm case). And finally, models for the Apple Watch ULTRA and ULTRA 2 (49mm case).