Abstract: A head/neck adjusting device includes a base, a clamping member, a holder, an adjusting and fastening knob, a plurality of locking members, and a head/neck support. The clamping member is clamped on a backrest of a chair. The holder includes a linear adjusting member inserted through the base, and an angle adjusting member connected with the linear adjusting member. The adjusting and fastening knob extends through the base and the linear adjusting member. Each of the locking members is mounted on the angle adjusting member and provided with a positioning projection. The head/neck support is provided with a plurality of support posts extending through the locking members. Each of the support posts is provided with a plurality of positioning holes, and the positioning projection of each of the locking members is positioned in one of the positioning holes.

Abstract: A stool apparatus is provided for a chair. The chair includes a base, a post installed on the base and a seat installed on the post. The stool apparatus includes a stool, a carriage and a telescopic device. The carriage is used for carrying the stool. The telescopic device is used for connecting the carriage to the post.