For bicycles with 1" 1/8 stem The Bobike A-Head Adapter Plus allows Bobike front seats to be installed on A-head stems with limited mounting space. With this A-head set, the required installation space is only 4 mm. The A-Head Adapter Plus is designed for adjustable stems, e-bikes with a monitor or controller at the top of the stem and MTB with 1" 1/8 stems. The A-Head Adapter Plus is designed for adjustable stems, e-bikes with a monitor or controller at the top of the stem and mountain bikes with 1 1/8 inch stems. Compatible with all Bobikes front seats and a windshield can also be used normally. Bobike mounting set Ahead Plus integrated cables. Also fits standard A headsets. Requires only 5mm mounting space. This set replaces the original bracket of the Go, One and Exclusive mini seats, but is also ideal as an additional attachment to a second bicycle. This way you can easily change your front seat, without needing any tools.