Warning about the threads, and some help with installation
First, I will say that the overall build quality seems high. Having said that, the threads in the valve body are a deal killer, causing me to return the kit.
The description says the threads are 1/2 NPT (standard US tapered pipe threads). The instruction sheet says they are G 1/2 (British parallel threads). In fact, they are neither. The thread size and pitch are the same as NPT, like the American system, but they are parallel rather than tapered, like the British system. The upshot is that neither NPT nor G 1/2 fittings fit properly. NPT fittings bottom out in the valve body without ever getting tight. The only way to get the threads to seal (and I should probably put seal in quotation marks) is to wad up many, many, many wraps of teflon tape. This valve will be enclosed within a wall, completely inaccessible behind thousands of dollars worth of tile work. In the end, I was simply not comfortable trusting my house to a wad of teflon in an improperly fitting connection. By the time you realize that your teflon wad started leaking, you have thousands of dollars of water damage.
Following communication with the seller, I surmise that at some point the manufacturer tried to change from G 1/2 to NPT, and while they got the thread size and pitch correct, they apparently didnt understand that NPT threads NEED to be tapered in order to tighten the fitting. The T in NPT stands for tapered! If they ever correct this issue, I would have no problem with installing this unit. As it is, though, you are forced to trust a bastard installation. Not worth the risk. Note too that this unit is sold under a bazillion different brand names, both here and in some big box stores. The seller is not the manufacturer, so cannot help you with such issues.
Secondly, the instruction sheet is almost completely worthless. Here are a few correct measurements to help you with the installation. Took me a lot of head scratching to figure these out from the cryptic instructions: The blocking for the valve body needs to be 2 behind the face of your studs. If you have 2x4 studs, you will need a piece of 2x material mounted on the flat, all the way back against the wallboard on the back side of the wall. When you mount the valve and add 1/2 of backer board and 1/2 of tile and mud, you will end up with the required 3 of setback.
The blocking for the drop-ear elbows for the shower head and the sprayer needs to be 1-1/2 back from the face of the studs. For this, use a piece of 2x material and a scrap of 1/2 plywood as a spacer. Note, though, that for the drop elbow and the shower arm to fit properly, the threads of the pipe elbows need to be at least flush with the surface of the backer board, if not the tile. The instructions say the threads should be 1/8 below the surface of the backer board, but if you do this and use 3/8 tile there will not be enough room left on the drop elbow for the escutcheon plate. You will therefore need at least two of these fittings to bring the threads to where they need to be: https://www..com/gp/product/B000BQY8E2/
Hope this helps.
Warning about the threads, and some help with installation
First, I will say that the overall build quality seems high. Having said that, the threads in the valve body are a deal killer, causing me to return the kit. The description says the threads are 1/2 NPT (standard US tapered pipe threads). The instruction sheet says they are G 1/2 (British parallel threads). In fact, they are neither. The thread size and pitch are the same as NPT, like the American system, but they are parallel rather than tapered, like the British system. The upshot is that neither NPT nor G 1/2 fittings fit properly. NPT fittings bottom out in the valve body without ever getting tight. The only way to get the threads to seal (and I should probably put seal in quotation marks) is to wad up many, many, many wraps of teflon tape. This valve will be enclosed within a wall, completely inaccessible behind thousands of dollars worth of tile work. In the end, I was simply not comfortable trusting my house to a wad of teflon in an improperly fitting connection. By the time you realize that your teflon wad started leaking, you have thousands of dollars of water damage. Following communication with the seller, I surmise that at some point the manufacturer tried to change from G 1/2 to NPT, and while they got the thread size and pitch correct, they apparently didnt understand that NPT threads NEED to be tapered in order to tighten the fitting. The T in NPT stands for tapered! If they ever correct this issue, I would have no problem with installing this unit. As it is, though, you are forced to trust a bastard installation. Not worth the risk. Note too that this unit is sold under a bazillion different brand names, both here and in some big box stores. The seller is not the manufacturer, so cannot help you with such issues. Secondly, the instruction sheet is almost completely worthless. Here are a few correct measurements to help you with the installation. Took me a lot of head scratching to figure these out from the cryptic instructions: The blocking for the valve body needs to be 2 behind the face of your studs. If you have 2x4 studs, you will need a piece of 2x material mounted on the flat, all the way back against the wallboard on the back side of the wall. When you mount the valve and add 1/2 of backer board and 1/2 of tile and mud, you will end up with the required 3 of setback. The blocking for the drop-ear elbows for the shower head and the sprayer needs to be 1-1/2 back from the face of the studs. For this, use a piece of 2x material and a scrap of 1/2 plywood as a spacer. Note, though, that for the drop elbow and the shower arm to fit properly, the threads of the pipe elbows need to be at least flush with the surface of the backer board, if not the tile. The instructions say the threads should be 1/8 below the surface of the backer board, but if you do this and use 3/8 tile there will not be enough room left on the drop elbow for the escutcheon plate. You will therefore need at least two of these fittings to bring the threads to where they need to be: https://www..com/gp/product/B000BQY8E2/ Hope this helps.