Big Beamer Wireless Transmitter brings reliable, immediate switch access without the hassle of cords. Multiple Big Beamers can be used in the same room at the same time, from as far away as 30-feet, without interference. Big Beamer Wireless Transmitter Features: Long battery life with built-in sleep mode Unique wireless codes eliminate cross-talk between devices 30-foot range with no pointing necessary Requires the Original Receiver Switch tops included: Red, Yellow, Green, Blue Technical Specifications Switch Type: Mechanical Connection Type: Wireless Activation Type: Pressure Activation Surface: 5-in/12.7-cm diameter Activating Force: 5.5-oz/156-g Travel Before Activation: 0.045-in/0.1143-cm Feedback: Auditory click, Visual, Tactile Mounting Plate: Universal Mounting Plate Product Dimensions: 6.375-in L x 6.375-in W x 1.35-in H (16.2-cm L x 16.2-cm W x 3.5-cm H)