"Please explain your reducing nipple?"
The threads are standard 3/4" male (ips) on one side and standard 1/2" male (ips) threads on the other side with very little room in between. Generally in the plumbing industry this would be considered a "close" nipple and it is called a 3/4" x 1/2" reducing nipples.

"Are your nipples made out of pipe (threaded) or are they molded nipples?"
It depends on the size and manufacturer. We think either style works equally well; but if this is important to you, please do ask before you place an order if we have whichever style that you would like, please specify on your order which style that you "must have".

"Do you recommend using PTFE thread sealing tape on PVC threads?"
Lasco Manufacturing says: "It is wrong to add excess bulk to a threaded joint by wrapping male threads in Teflon® tape. It is wrong to make over-tightening easier by using Teflon® tape..." We have seen much similar PTFE thread sealing tape used satisfactorily but cannot (due to liability potential) recommend that you use PTFE thread sealing tape (pipe dope designed for PVC, such as we offer above, is acceptable).

"I see the word Close' as one of the length options? How long is 'close'."
That depends on the size and the brand. "Close" simply means that there is no space between the threads on the body of the nipple. It is as short a nipple as possible.