There are peashooters and there are the other peashooters.
My first Commando was in 1973. The original peashooters were the perfect sound on those bikes.
Mellow, but loud enough when you pin it.
I don't know what the original construction of those was.
AFIK all that's available now are pattern types.
There are a few available, both English and Chinese.
The one's I recently bought are the most commonly available from your local BritBike dealer. They are 1 3/8 inlet only and specifically designed to bolt on to a T140. Low price and very good looking.
They are straight through, carrying the 1 3/8 inlet size right to the end.
They are way too loud for me, almost sound like TT pipes.
They come with the pre-1983 disclaimer sticker
Don't know who makes them but they must be Chinese because the price was so low. (Emgo?)
They're not doing my image any good with the neighbors.