Abstract: A reaction receptacle apparatus includes one or more individual receptacles for containing chemical or biological substances. The one or more receptacles are arranged to be engaged by tubular elements of a substance transfer device for transferring substances into or out of the individual receptacles. Multiple receptacles are coupled to one another by a connecting rib structure that defines straight shoulders along opposite sides of the reaction receptacle apparatus, and the shoulders support the apparatus within reaction receptacle apparatus carrying structures. A contact-limiting element holding structure for holding contact-limiting elements, such as protective tips for tubular elements, is associated with each individual receptacle and holds a contact-limiting element in an operative orientation so as to be operatively engageable by the tubular element of the substance transfer device.