Standard / Skeleton Back Door Mount Backdoor Mounts 4 Pcs for GoPro Hero 3+, Hero 4 Camera - Black (2 Pcs Compatible with GoPro Hero 3) Compatible with GoPro Hero3+ and Hero4 standard and skeleton housings Compatible with GoPro sportsman mount Allows more mounting solutions Made of durable lightweight ABS plastic Package included: Standard Backdoor Mount x 2; Skeleton Backdoor Mount x 2 (two fit Hero3+ / Hero4 original housing, another two fit housing that compatible with Hero3); Free touch screen stylus pen is included (Random color shipped)