Abstract: This invention relates to a system for amplifying a sound in an auditory environment. The system comprises a microphone for transforming said sound to an electric sound signal; a band-pass filtering means connecting to said microphone and outputting a filtered sound signal; and an amplifier amplifying said filtered sound signal and outputting a filtered and amplified sound signal to a loudspeaker. The band-pass filtering means comprises a passive first filter having a first bandwidth and first gain, an active second filter having a second bandwidth and a second gain larger than said first gain, and an active third filter having a third bandwidth and a third gain larger than said second gain.

Abstract: The present invention is directed to a syringe with a retractable needle guard. The syringe has two coaxial tubular bodies, an inner and an outer body, which are adapted to telescope in relationship to each other. The outer tubular body is adapted to at least partially receive the body of the container from which fluid is to be drawn and the inner tubular body is adapted to be displaced from a retracted position to an advanced position. In the retracted position the needle is exposed, while in the advanced position the needle is surrounded by the inner tubular body. The syringe with a retractable needle guard may also be adapted to connect the outer tubular body with the needle without connecting it to the container from which fluid is to be drawn.