DarkSide 4-PIN Molex + RPM Wire to 3-PIN Fan Conversion Cable - 30cm Jet Black Sleeved (DS-0525) ModMyMods.com - PC Watercooling Parts and Accessories
1.25mm Pitch 3-pin Cable Matching Pair - 40cm long [Molex PicoBlade Compatible] : ID 4721 : $0.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Kotyreds 2pcs 4-Pin Molex to 3-Pin fan Power Cable Adapter Connector 12v*2 / 5v*2 - Walmart.com
8 inch Molex 4pin to 3pin TX3 CPU / Case Fan Male Power Adapter Converter Cable w/ 4inch Molex 4pin Female Extension Port Saver Internal Power Cables - Newegg.com