The makers of this product have it made. Anyone who is installing a shower where there used to be a tub and you’re on slab will probably need this. This seems to be the only company that makes it. Our shower/tube combo that came with the house uses a standard (for tubs) 1.5 inch drain and pipe. Showers are 2”. Sure, you can get a pvc reducer at the hardware store but if you’re on slab like us, there’s likely not enough room to dig out the space you need to have the 2” drain, then a reducer down to the 1.5 pipe, (without digging to the earth’s core). This was worth the money and solved our problem.