it is used with both as best shown in fig5 and 6 the support fixture includes a mounting bracket 65 affixed to the casing 66 of the bath tank structure 15 in a conventional manner as by welding an offset tubular arm 67 has its lower leg received within a corresponding sleeve or collar 68 of the mounting bracket 65 a threaded clamping screw 69 on the sleeve 68 is adapted to be tightened against the lower leg of the tubular arm 67 and secured in the selected position relative to the bracket 65 the tubular members 53 and 54 of the holding device 47 or the tubular members 57 and 58 of the adjusting mechanism 56 are received within the recessed center portion of a base plate 70 affixed to the top of the upper leg of the tubular arm 67 a clamping strap 71 is urged downwardly against the tubular members as by a bolt 72 passing through the base plate and clamping strap to secure the tubular members therebetween it will thus be apparent that by proper manipulation of the support fixture 64 the holding device 47 and the adjusting mechanism 56 can be utilized to swing the extension tiles 42 about their respective pivot pins 50 to the desired angular position and to hold the tiles in this position more particularly the tubular arm 67 can be raised lowered and rotated within the sleeve or collar 68 while the tubular members 53 54 and 57 58 can be moved longitudinally.