Abstract: A head-mountable device can include a fan that effectively manages heat while also mitigating the intrusion of particles and other debris. Fans can include a protrusion that creates a tortuous pathway to direct incoming particles away from sensitive regions. Fans can include openings to allow particles to exit the fan enclosure and avoid interaction with the impeller. Fans can include a variable spacing between the impeller and the base plate to avoid collection of particles. Fans can include an adhesive pad that collects and retains particles at a location that does not interfere with rotation of the impeller.

Abstract: A device for adapting a cover for an existing air filter assembly to seal an end portion of a replacement cylindrical air filter having a round cross-sectional shape is disclosed. The cover has a plate with a radially inner convex guide separated from a radially outer convex guide by a concave receiver, a tightening member connected to the plate, and a catch having a first end movably connected to the tightening member, and the catch having a second end configured to engage a keeper, the tightening member adjustable to vary a distance between the catch and the plate. An adaptor is attachable to the plate of the cover. The adaptor has a first side for engagement with the plate and an opposing second side for engagement with an end portion of a cylindrical filter. The first side has a sealing surface extending radially inwardly from a peripheral edge.

Abstract: A device for adapting a cover for an existing air filter assembly to seal an end portion of a replacement cylindrical air filter having a round cross-sectional shape is disclosed. The cover has a plate with a radially inner convex guide separated from a radially outer convex guide by a concave receiver, a tightening member connected to the plate, and a catch having a first end movably connected to the tightening member, and the catch having a second end configured to engage a keeper, the tightening member adjustable to vary a distance between the catch and the plate. An adaptor is attachable to the plate of the cover. The adaptor has a first side for engagement with the plate and an opposing second side for engagement with an end portion of a cylindrical filter. The first side has a sealing surface extending radially inwardly from a peripheral edge.

Abstract: A device for adapting a cover for an existing air filter assembly to seal an end portion of a replacement cylindrical air filter having a round cross-sectional shape is disclosed. The cover has a plate with a radially inner convex guide separated from a radially outer convex guide by a concave receiver, a tightening member connected to the plate, and a catch having a first end movably connected to the tightening member, and the catch having a second end configured to engage a keeper, the tightening member adjustable to vary a distance between the catch and the plate. An adaptor is attachable to the plate of the cover. The adaptor has a first side for engagement with the plate and an opposing second side for engagement with an end portion of a cylindrical filter. The first side has a sealing surface extending radially inwardly from a peripheral edge.