An underwater communications system is provided that transmits electromagnetic andor magnetic signals to a remote receiver. In one embodiment, the invention provides for devices and methods of training paracentesis procedures. During the final cure stage, a significant pressure can be applied by releasing the vacuum in one of the two environments. The attachment member can engage an electrical component thereby providing a gas-tight, solder free connection between the attachment member and electrical component. This results in a practically uniform distribution of effective radiation energy of radiation with a wavelength <320 nm over the radiation surface as a whole. The needle is automatically enclosed by the sheath using only one hand and without gripping the sheath.