椅座靠背個別操作，無段傾仰調整，整張座椅可前後擺動，更增舒適感，搭配背板，適合中型椅。

A tilter with spring tension control. Seat & back are independently adjustable and can be locked infinitely at desired tilting angels. Suitable for chairs of big size; but with different steel bar back stem.

Same as A-249-6A; but with different hole spacings. Suitable for medium size chair.