Diving equipment, apparatus and instruments, namely, self-contained underwater breathing apparatus, closed circuit rebreathers and semi-closed circuit rebreathers and integral parts therefor, cases for self-contained underwater breathing apparatus, closed circuit rebreathers and semi-closed circuit rebreathers; counterlungs, water traps, flexible breathing hoses, carbon dioxide scrubbers, open/close mouthpiece valves; underwater breathing apparatus; scuba diving equipment; breathing apparatus for divers, namely, rebreathers; parts of underwater breathing apparatus and scuba diving equipment, namely, sensors, monitors, controllers, gauges, inflators, valves, regulators, hoses, hose clips, covers, connectors and couplings, to monitor and control oxygen, carbon dioxide and inert gas levels, gas cylinder pressure, to monitor and control performance of self-contained underwater breathing apparatus, to monitor, record, control and warn of oxygen partial pressure, to monitor, record, and warn of carbon dioxide content, to monitor dive statistics, to monitor, record, compare, analyse and warn of dive depth, dive time, dive profile, ambient temperature, water temperature, atmospheric pressure, time, date, battery voltage, battery status, scrubber status, scrubber duration, scrubber performance, ascent warnings, decompression ceilings, decompression times, decompression safety margins and surface interval between dives; electronic and electrical apparatus, instruments and equipment for use under water and as parts of underwater breathing apparatus and scuba diving equipment to monitor and control oxygen, carbon dioxide and inert gas levels, gas cylinder pressure, to monitor and control performance of self-contained underwater breathing apparatus, to monitor dive statistics, to monitor, record, control and warn of oxygen partial pressure, to monitor, record, and warn of carbon dioxide content, to monitor, record, compare, analyse and warn of dive depth, dive time, dive profile, ambient temperature, water temperature, atmospheric pressure, time, date, battery voltage, battery status, scrubber status, scrubber duration, scrubber performance, ascent warnings, decompression ceilings, decompression times, decompression safety margins and surface interval between dives; computer hardware and downloadable computer software for use in relation to underwater breathing apparatus and scuba diving equipment to monitor, log, analyse, control, record and display information regarding dive statistics, oxygen, carbon dioxide and inert gas levels, gas cylinder pressure, performance of underwater breathing apparatus, to monitor, record, control and warn of oxygen partial pressure, to monitor, record, and warn of carbon dioxide content, to monitor, record, compare, analyse and warn of dive depth, dive time, dive profile, ambient temperature, water temperature, atmospheric pressure, time, date, battery voltage, battery status, scrubber status, scrubber duration, scrubber performance, ascent warnings, decompression ceilings, decompression times, decompression safety margins and surface interval between dives; sensors, monitors and controllers for underwater breathing apparatus and scuba diving equipment, namely, gas cylinder pressure sensors, oxygen pressure sensors, carbon dioxide pressure sensors, temperature sensors, pressure sensors; measuring apparatus and instruments for underwater breathing apparatus and scuba diving equipment to monitor and control oxygen, carbon dioxide and inert gas levels, gas cylinder pressure, performance of underwater breathing apparatus, to monitor, record, control and warn of oxygen partial pressure, to monitor, record, and warn of carbon dioxide content, to monitor dive statistics, to monitor, record, compare, analyse and warn of dive depth, dive time, dive profile, ambient temperature, water temperature, atmospheric pressure, time, date, battery voltage, battery status, scrubber status, scrubber duration, scrubber performance, ascent warnings, decompression ceilings, decompression times, decompression safety margins and surface interval between dives; downloadable and/or recorded electronic instruction manuals in relation to underwater breathing apparatus and scuba diving equipment; dive computers for underwater use; decompression dive computers for underwater use; data processing apparatus; data communications equipment, namely, LED display units for underwater use, liquid crystal display units for underwater use and electronic display units for underwater use, electronic display interfaces for underwater use, electric luminescent display screens for underwater use, wearable video display monitors for underwater use; warning lights for underwater use; visible notification appliances for underwater use; audible alarms for underwater use; audible notification appliances for underwater use; mono-tone and multi-frequency piezo operated buzzers and speakers; apparatus for recording, transmission or reproduction of sound or images or data, all the aforementioned being for use in or in relation to underwater breathing apparatus and scuba diving equipment; air tanks and cylinders for underwater breathing apparatus and scuba diving; cylinder bands, namely, brackets and bands for divers' air tanks, cushioning pads for divers' air tanks, cylinder mounting boots for divers' air tanks, attachments and back plates for divers' air tanks, harnesses for air tanks for underwater breathing apparatus and scuba diving; scuba divers' weights and weight belts; surface marker buoys; apparatus for divers, namely, buoyancy bladders, buoyancy compensators or devices for divers, buoyancy jackets and life jackets for scuba divers; parts and fittings for all the aforesaid goods; kits comprising diaphragms, seals, O rings, springs, valves, filters, hoses, hose connectors, bearings for maintaining and servicing the aforesaid goods