Lally Lock system is a height-adjustable Lally column. It has three parts: a steel-encased concrete column with a coupling nut embedded at the top, a steel top plate, and a steel baseplate/bearing-plate combination with 3-inch adjustment bolts. You bolt the top plate to the coupling nut and fasten the base plate to the bottom of the column with concrete screws. Then you position the base plate over the coupling plate and tighten the bolts to secure the column at the correct height. Columns are sold in 3-inch increments; an 8-foot by 31/2-inch column plus hardware costs around $90.
Dean Column, 800/442-3455, deancolumn.com.