New old stock Gruvlok Fig. 7250 4 inch suction diffuser.  Surplus assets priced to move.  Yes, these are the same diffusers sold by supply houses for $2,500 or more.  I want to sell them quickly so I'm pricing these at the lowest price on the Internet.  Supply houses are showing a 4-8 week backorder.  I have them on the shelf ready to ship today.