About the D'Addario PW-CP-10 Artist Capo:
 
The Artist Capo utilizes a patented Tri-Action geometry reducing the force required to open and close the capo while applying even tension regardless of neck profile. Combined with the micrometer tension adjustment and direct horizontal pressure, the Artist Capo virtually eliminates pulling the strings side to side and the need to retune during use. Additionally, the trigger-style design and lightweight aluminum construction add no obstruction or noticeable weight to the neck of the instrument. The Artist Capo includes a pick holder bracket, a micro tuner mounting bracket, allowing you to add tuning capabilities to the capo. Tuner sold separately. Designed in collaboration with Ned Steinberger US Pat. 8,779,262