Wireless outdoor air quality monitor measures PM2.5 particles, display shows indoor temperature, humidity and the outdoor PMI/AQI figures. Outdoor monitor uses rechargeable batteries charged from the solar panel on top.
Outdoor monitor is a bit discoloured from sunlight, but it's all in working order.
Wireless air quality monitor (Finchampstead RG40)
This offer has been gifted to someone and is no longer available.