The invention relates to a pressure-sensitive adhesive. An electronic stethoscope sensor is contained within a housing for transducing body sounds to electronic signals, and is operatively connected to the electronic processor. The epoxy compound functions not only as a hardener for the phenolic resin but as a trapping agent for free phenol. A plurality of different secondary housing sections having a second mounting interface which can be attached to the first mounting interface of the base housing section are provided. In one embodiment, the player has the opportunity to see the different paytable prior to paying the fee to purchase it. The source and drain electrodes may have a structure including an aluminum layer, an aluminum-nickel alloy layer, and an indium tin oxide layer, which are sequentially stacked.