A headrest assembly for a chair (9) includes a headrest unit (3), two spaced-apart grip frame members (23) respectively connected to two opposite ends of the headrest unit (3), and two spaced-apart connection frame members (21) respectively connected to th...

A USB converter adaptor for a mobility assistive device includes a mobility assistive device connector (3), a DC-to-DC converter (4) and a USB connector (5). The mobility assistive device connector (3) includes a tubular casing (33) and two conductive pins...