Instruction: Parse the product information to locate the target attribute, and then provide the extracted value of the target attribute and its source in the output, specifying None if the attribute is not present.

Input:
Product title: Rockstick Ergonomic Mouse RS1201M Black and Gray Small/Medium
Product description: The Rockstick Ergonomic Mouse is the worlds first vertical ergonomic mouse that allows users to click by utilizing the strength of the entire hand instead of fingers alone. The Rockstick Mouse features an integrated palm support that prevents the wrist anchoring related to increased carpal tunnel pressure and wrist extension. Featuring a vertical handle allowing the hand to remain in the handshake position. This position is known to eliminates forearm twisting and minimize pressure in the carpal tunnel area of the wrist. With the Rockstick Mouse you no longer click with your fingers! Instead, you click utilizing your entire hand and avoid the painful problems associated with repetitive finger overuse. (If left unaddressed, the repetitive motion and overuse of fingers results in inflammation and swelling of the finger tendons. These swollen tendons squeeze the median nerve running from the forearm into the hand and eventually lead to Carpal Tunnel Syndrome). Benefits: The purpose and benefit of the Rockstick Mouse is to relieve and/or prevent computer-related mouse injuries, in particular, the numbness, weakness, tingling and pain associated with Carpal Tunnel Syndrome (CTS). Determine size by measuring the width of palm at the knuckle point. 2.75" - 3.75" is Small/Med, 3.75" - 4.25" is Large. Compatible with Windows 98, ME, 2000, XP, Vista, 7 and MAC OS 9 or later - Right hand only.
Product feature: Determine size by measuring the width of palm at the knuckle point. 2.75" - 3.75" is Small/Med, World's first vertical ergonomic mouse that allows users to click by utilizing the strength of the entire hand instead of the fingers alone, Integrated palm support eliminates wrist anchoring, Upright natural grip allows comfortable handshake position, Memory foarm wrist-rest included for added comfort
Product price: $59.00
Product brand: Rockstick Inc
Target attributes: Number of Buttons
Answer: attribute: number of buttons
value: None
source: None