Rating: 4 / 5
This is a 0.7 oz sensor roughly the size of a fountain pen:
It features min/max capture for both temp and humidity. Temp accuracy is stated to two degrees. Humidity to +- 5%. Purchased through Amazon for 21.95 plus shipping; I can now no longer find it at this price or from the seller I purchased it from.
Operation is straightforward with no cryptic multiple-use button sequences. There are power, display min/max/current readings, F/C units select, and min/max clear buttons. Min or max temp displays are indicated by down and up arrows respectively on the display. The clear key works only when the min or max is being displayed. The LCD display is big and clear enough for me to read without my glasses.
Close-up of display showing the max arrow:
Powered by an LR44 button battery, life is unstated by the manufacturer. I am currently testing it by leaving it on until the first battery dies.
Detail of the back showing mounting clip and battery access:
Unfortunately, I had to downgrade the device to a 4 rating because the min/max clears on power off; the power button is rather easy to press accidentally.
I plan on using this to record minimum nighttime temps so that I can compare my comfort level under different conditions with my sleep gear (MLD large 3-layer Spirit Quilt) and insulated clothing backup.