I make an industrial model. To reduce cost, the level of finish is somewhat less than on the other models. The brass bridges are not polished just sanded to 400 grit. The wood has multiple coats of urethane. Their sounding elements (rods and weights) are the identical to the other models and same care goes into the tuning the industrial models The sound board is made of ½” thick Padauk and the bridges are made of ½” by 1 ½” brass bar stock. These are very rugged and do weigh more than the other models. Their sound quality and volume is comparable to the other soundboard only models. These are available in 8-7, 10-9 and 13-12 sizes.