Excelity 2 Channel DC 5V Relay Module for Arduino Raspberry Pi DSP AVR PIC ARM - - Amazon.com
Pololu Basic SPDT Relay Carrier with 5VDC Relay (Assembled)
Amazon.com: 5vdc (5 Volt DC) Relay - DPDT PCB 8-Pin Mount - Non-Latching Non-Polarized Electronic Low Signal High Sensitivity Relay Module for DIY Electronics and Arduino : Industrial & Scientific