The description from Astro-Physics:
2" Extension Tube with brass locking ring, 1.75" long, 48mm threads (this is also part of our Convertible Barlow)
I bought this last week from Astro-Physics and the length didn't work for my application. No marks, or scratches, indistinguishable from new; only slipped into the focuser twice with an eyepiece to confirm that it wouldn't work for my project.
Price from AP is $45.00. I'm asking $37.00 shipped CONUS. PayPal, check or Money Order.
Thanks for looking,