Soft 4x4 Keypad Matrix lets you quickly add controls to your electronics projects. It offers 0-9 numerals, A-D letters, and standard star(*) and hash(#) symbols. 

Features: 

16 Button Matrix
0-9 # * A-D
Excellent price-performance ratio 
Easy communication with any microcontroller

Contact resistance of 500 (Ω) 
Insulation resistance 100M (Ω) 
Key Operating Force 150-200N 
Rebound time 1 (ms) 
Life of 100 million (times) 
Operating Temperature 60 (?)

the electronic characteristics 
Circuit Rating: 35V (DC), 100mA, 1W 
Contact resistance: 10Ω ~ 500Ω 
(Varies according to the lead lengths and different from those of the material used) 
Insulation resistance: 100MΩ 100V 
Dielectric Strength: 250VRms (50 ~ 60Hz 1min) 
Electric shock jitter: <5ms 
Life span: tactile type: ≥ one million times