Covers -
Fender's form fitted heavy fabric Dust Covers for the Mustang Amps I/II/III/IV/V and V 4x12 cabinet are durable and well made from Black heavy weight vinyl backed fabric and have the Fender Logo. They have reinforced sewn edges and an opening for the Amp's handle. All Amp cables and cords must be disconnected for the cover to fit. When not in use the cover is easily folded for storage (and can be stored in the open back of the Mustang III/IV).
Amp Stands -
Amp stands can be useful to better position an Amp and can improve sound in instances when leaving the amp on the floor may result in undesirable mechanical and acoustical coupling to the floor, walls, and corners. Amp Stands are available in a variety of designs and price points.
With the Mustang III and IV Amps' open backs, most amps stands will not work without some sort of supplemental cross bracing to support the stand's rear support arms.
One exception is the On-Stage RS7500 Tilt Back Tripod Amp Stand. The RS7500 is a heavy duty adjustable stand quite well suited for the Mustangs. The stand is very stable, folds compactly, and is easy to transport. The RS7500 has five (5) lockable tilt back positions and is rock solid. The hinged lower support arms and telescoping upper section are cushioned at all Amp contact points. Atop the stand is a standard mic stand thread that provides a convenient mount for a horizontal or flex boom to easily mic the amp. The stand does not block any jacks when used with the Mustangs.
The StageLine Stands AS5 Amp Stand , is a heavy duty & sturdy option if you want to elevate your amp 12"-19" at a 30° tilt back. For the Mustang MIII/IV Amps, extension sticks for the stand's rear support arm brackets are an easy and inexpensive enhancement. These slide into the rear support arm brackets after the plastic end caps are removed. Oak sticks are commonly available at hardware stores and lumber yards sized: 2' x 1/2" x 1". Rip about 1/8" from both edges along 10" from one end of the stick for suitable insertion length, and sand or plane a bit to thin the inserted portion to fit. When complete they resemble a short boat oar. A cut to size strip section of peel and stick black foam weatherstripping may be adhered to the extending portion to cushion the back of the amp and match the original arm brackets. They work great! Leaving a bit of extra length extending above the top of the amp cabinet acts as a handy place to loop a cable, etc. The height adjustable rear bracket arms are swappable (from side to side) to change the tilt back angle. If you do, be sure your amp's center of gravity remains stable!
Power Conditioners -
USB Extension Cables -
For running FUSE on a PC or Mac, or Remuda on an Android Smartphone or Tablet, beyond the several feet supported by the Fender provided USB cord, a standard 10' USB 2.0 compliant extension cable works fine! However, beyond the approx 15' combined distance of Fender's cable connected to a 10' USB extension, the signal begins to faulter. In this case you need a USB cable with active electronics to amplify (aka repeat) the USB signal. I successfully use the Sabrent CD-USBXT 32 foot long USB 2.0 Active Extension Cable USB 2.0 Active Extension Cable. I got this at Fry's Electronics for under $15 and it did the trick! For Fender Mustang Owners who want to run FUSE beyond 32' from their Mustang Amps, consider Sabrent's Active USB 2.0 Extension cables in 65' or 100' lengths. These are also fully USB 2.0 480Mbps compliant using Active components powered by the PC's or Mac' USB port. For even greater reach they make a 150' Extension kit that is only ISB 1.1 compliant. This converts the USB signal to Ethernet and supports up to a 150' run using Cat5e or Cat6 cabling. [Note: Android's USB Port Host Mode does not support use of the Active Extension cables.]