Mono Enclosed Speaker - 3W 4 Ohm : ID 3351 : $3.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Mini Audio Portable Speakers 4 Ohm 3w Diameter 40mm Full Range Speaker Diy Stereo Home Theater Woofer Loudspeaker - Instrument Parts & Accessories - AliExpress
2 Inch 4 Ohm 3w 52mm Audio Speaker Multimedia Speaker Accessories | Fruugo FI