Abstract: A knife and sheath combination having an interlock formed of a tab to carry an inwardly extending dog that is mounted on a laterally flexible stem to the sheath. The dog may be moved laterally to and from an interfering engagement with a stop carried on the handle of the knife.

Abstract: A knife and sheath combination having an interlock formed of a tab to carry an inwardly extending dog that is mounted on a laterally flexible stem to the sheath. The dog may be moved laterally to and from an interferring engagement with a stop carried on the handle of the knife.

Abstract: A device for attaching a shoulder strap to a fabric wall of a backpack comprising a pair of flexible reinforcing fabric members positioned orthogonally to each other and on either side of one end of the shoulder strap and further including stitches implemented in a box stitch pattern which secure one of the fabric members to the strap and additional stitches securing the strap, both fabric members and the fabric wall of the backpack together.

Abstract: A diving snorkel is provided comprising a mouthpiece assembly attached to a breathing tube. First and second purge valves are located in a side wall of the mouthpiece assembly. A partition is disposed in the side wall, between the two purge valves, so as to partially divide the breathing chamber into first and second sections. The first section includes the first purge valve which lies directly in the path of air exhaled from the diver's mouth. The second section contains the second purge valve which is blocked from the direct flow path of the air from the diver's mouth by the partition but does receive some air which flows around the end of the partition into the second section. The partition is inclined so as to direct water to flow, by force of gravity, from the first section to the second section. Another surface directs water within the second section towards the second purge valve.

Abstract: A sheath and knife combination providing an interlocking fit when the knife is inserted into the sheath. The sheath is provided with two upward extensions having a resilient leaf on one extension oppositely facing a hole on the other extension. The knife has two buttons disposed on opposite surfaces of the knife handle and connected by a shaft. When the knife is fully inserted into the sheath, the leaf contacts one of the buttons thereby forcing the opposing button into the hole so that the knife and sheath become interlocked. The knife may be removed from the sheath by pushing the button which engages the hole and pulling the knife out of the sheath.

Abstract: A knife and sheath in combination in which a two-headed bolt supported in the knife handle may be positioned to interlock with the sheath. The bolt is symmetrical with respect to the knife to permit insertion of the knife into the sheath in either direction. The sheath has a portion of a resilient flexible wall positioned to engage one head of the bolt to urge the other into a hole in the other side of the sheath to secure the knife within the sheath until the bolt is pushed firmly in the opposite direction to disengage the knife and the sheath.

Abstract: A swim fin having an elongated flexible blade. The blade has elongated tapered sleeves to hold elongated tapered battens. The battens selectively stiffening the blade to achieve varying degrees of stiffness according to the wear's strength. Each batten has a tab to function to prevent the batten from sliding entirely within the sleeve and to function as a grip for easy removal of the batten from the sleeve. Additionally, the fin has ribs with concave outer walls which assist in the smooth flexing of the fins when used.