The newly designated 3931A also encompasses the celebrated features of the previous generation 3931, including the pulse-clean electro-magnetic automatic filter cleaning system. Whether sanding or routing in the shop or concrete surface grinding or tuck pointing high on a scaffold, a power tool activated vacuum that constantly trips circuit breakers wastes time and money. For this reason, Bosch developed the new power broker system, which allows users to utilize the entire amount of available power 15-Amps on a 15-Amp circuit, 20-Amps on a 20-Amp circuit and allocate it between the vacuum and a connected power tool. Additional 3931A enhancements include new rear wheels and metal front casters with rubber tires for easy transport across all types of surfaces. And a new special stiff rubber swivel nozzle ensures a quick and snug connection to vacuum cleaner attachments, Bosch power tool dust ports and Bosch adapters for other power tools. The innovative Bosch 3931A airsweep vacuum also includes the same celebrated features of the previous generation unit. Superior suction power is derived, in part, from the large surface areas of its unique U-shape twin filters. Positioned out of the direct flow of incoming debris and above the reach of the dust or liquid that has already been vacuumed, the standard filters will capture 99.93-Percent of all particles 3.0 microns and larger in diameter. Furthermore, the 3931A has the quickest and easiest filter change system on the market, allowing users to simply open the lid and drop replacements in.