Surgical and medical apparatus and instruments including syringes for injections, syringes for medical purposes, single use syringes, surgical scalpels, surgical scalpels with retractable guards, attachments for syringes to prevent needlestick including shrouds covers and guards for attachment to syringes, catheters, needle assemblies attachable to catheters, needle assemblies attachable to catheters and which operate under vacuum, which operate using an elastomeric member and which operate using a spring or other type of biasing member, valves for medical or surgical use, including valves attachable to a syringe to regulate flow direction, one-way valves for medical or surgical use including one-way valves attachable to a syringe to regulate flow direction, back flow prevention valves including back flow prevention valves attachable to the front of a syringe, needles for medical purposes, stabilising devices for gas cylinders for medical use, stabilising devices for gas cylinders, trolleys for transporting gas cylinders especially gas cylinders for medical use, devices for transporting gas cylinders especially gas cylinders for medical use