Flying W Model M ESP Stem (Generation 2)

"Flying W/ESP stems were made in Tacoma, Washington in the early 80's by Walt Ehnat (Flying "W") and his son, racer Marty Ehnat. The ESP stem was basically the first XL/Long stem introduced to the BMX market (around '82), and a lot of pros used and endorsed them."
~ http://bmxmuseum.com/reference/1106

"The Model "M" (for "Marty") 2nd generation round logo stem. Only 20 were produced with the stamp on the side. The quill was made long as they were installed high with flex fighters."
~ email attached to http://bmxmuseum.com/reference/1106

"Your E.S.P Stem is unique in the industry developed by a Pro Bmx'er with the aid of space age technology and material. 
The head parts are 7075-T-6 Aircraft grade aluminium - this material costs 5 times as much as 6061 Industrial grade aluminium most stems are mad from. This is why your bars will stay put with our Stem.
The shaft is stainless mandrel drawn Alloy Steel. Similar to gun barrel material. 
All bolts are T5... The allen head bolts are 5/16 American thread. 
Like buying a fine watch or gun - our product may cost a little more but you probably have bought your last stem.
No Stem should be elected more than 1 5/8" or we cannot honor our guarantee"
~ ESP Stem leaflet from the Gen 2 Model M.