This Peavey XXL 412 Slant Speaker Cabinet is in pretty rough shape cosmetically but in excellent working order.  The tone sounds great.

COPY FROM THE PEAVEY CUT SHEET:
The XXL 412 slant and straight cabinets are the ideal companions to the XXL and SupremeTM guitar amplifier heads, but are equally suited for any guitar amplifier. These full-sized enclosures are 16 Ohms, so they’ll work with most amplifiers. Peavey’s 144 Blue Marvel speakers make these the perfect companions to the TransTube® 100 EFX amplifier head, yielding a tone similar to that of the TransTube 212 EFX combo, but in a much bigger-sounding rig.

One interesting departure from the traditional slant-top cabinet is the use of a single-plane baffle, instead of the more common bi-plane approach. This results in less cancellations between the top and bottom pairs of speakers and allows the slant cabinet to sound much more like the straight cabinet. The added low end and less in-your-face tone produces much better half- stack tone than normal. The grille cloth is then braced off of the baffle to give the traditional look of a bi- plane baffle design.