A heart stimulator provides a reliable automatic capture threshold search feature. Thus, the catch cap catches the water flow and introduces the water flow through the water inlet hole into the air chamber so as to reduce the water flow rate, thereby achieving the purpose of saving water. The arrowhead assembly includes a media reservoir defining a cavity and a plurality of supports extending outward from the media reservoir along a longitudinal axis. Also provided by the host system, are questions relating to the products to be presented to a customer who uses the electronic catalog.