In one aspect, a tube device including concentric inner and outer tubes to form an annulus to receive an upright stem in a toilet tank and adjustable vertically and rotationally relative to the stem. In another aspect, an elongated catch device is pivotally mounted intermediately to an inlet tube device and carries at its upper extremity a keeper selectively disposed in the path of a float device to, unless a toilet has been flushed, block lowering of the float device and consequent opening of the control valve.