DYNAREX FINGER PULSE OXIMETER (7088). Medical Professional Model. Reads SPO2 and Pulse Rate!
Comes with 2-AAA batteries 
FREE!! This is a great buy!
-  Unbeatable accuracy - clinically tested
-  Drop tested durable and moisture proof
-  Simple one button operation
-  Suitable for the people whose finger thickness is between 1/3 inches and 1/2 inches
-  Great for home use too!