This elbow is very job specific and you would only use it if your local code allows this application. In some municipalities it is approved to attach a condensate drain to the overflow elbow because of the free flow through the overflow into the sanitary drains. This elbow should never be used unless a condensate drain is connected properly, because a leak can develop if it is not. You should always check with your local building officials before installing this type of drain connection. 
This corrosion is mainly a result of continuous exposure to harsh cleaning chemicals, and also if Zinc finish hardware is used. Dearborn Brass recommends brass components and the use of mild cleaning chemicals to avoid this issue.
The 203-3 and the 230-3 are specifically designed for deeper tub applications, and are the preferred choice for these tub installations. Always check with tub manufacture for dimensional restrictions. 
No. If you install a solvent weld half or full kit bath waste/overflow, access panels are not required. Remember that you may still need an access door if the faucet doesn’t have integral shut offs built into the faucet body. 
No.
All of our bath waste/overflows are designed to allow easy access for drain cleaning. Drains can be cleaned with a power cable by removing the faceplate cover, and any interior linkage that may be attached. Then push the power cable down through the overflow opening, and it will be guided directly into the trap and on through to the tub drain. 
The traditional trip lever – The lever on the faceplate moves up and down, and is connected to internal linkage attached to a barrel. When the lever is lifted up, the barrel drops down and blocks the flow of water out of the tub drain. The center of the barrel is hollow; this allows overflow water to pass through the barrel and into the drain pipes. Any water passing through the overflow when the barrel is in the closed position, will flow through the barrel and into the drain pipes.  The Uni-Lift Stopper – The stopper is lifted manually upwards with a slight twist to allow water to drain from the tub. With a small twist and a push down, the stopper will stop water from draining out of the tub. The Toe-Touch – When you push down in the center of the stopper, it will close and not allow water to drain out of the tub. When you push down off center, the stopper will pop up and the water will drain out of the tub. The Cable Drive – a concealed cable is connected to the bath shoe and overflow tube. When you turn the overflow plate, the stopper will be moved up and down.
Brass tubular bath waste/overflow trim kits are only available in Chrome finishes. Polyethylene plastic tubular bath waste/overflow trim kits are available in Chrome, Brushed Nickel and Oil Rubbed Bronze finishes. Please confirm your choice of trim kit finish is available with your choice of bath waste/overflow before you purchase the product. PVC or ABS full and half kits trim finishes include Chrome, Brushed Nickel, Antique Bronze, Biscuit, Oil Rubbed Bronze, Ultra Shine® Satin Chrome and Ultra Shine® Satin Nickel finishes. Please confirm your choice of trim kit finish is available with your choice of bath waste/overflow before you purchase the product. We also offer Plastic Tubular and Schedule 40 Cable Bath Waste Conversion kits in Chrome, Biscuit, Brushed Nickel, Oil Rubbed Bronze, Ultra Shine® Polished Brass, Ultra Shine® Satin Nickel and White finishes. Please confirm your bath waste/overflow can be converted before purchasing the product.   
There are four materials to choose from: 17 gauge brass tubular Polyethylene plastic tubular PVC full and half kits ABS full and half kits
You can use one of our thread tapes or pipe joint compounds to complete this application. If you are using thread tape, wrap the male threads on the tail piece 2 or 3 times, and then screw the tail piece into the pop-up body. After the drain has been tested and found to be water tight, you can cut the excess thread tape off if desired. If you use pipe joint compound, only apply it to the male threads of the tail piece and wipe off excess after the drain has been tested.