This mount fits:

Ruger MK I (Ruger Mark I)

Ruger MK II (Ruger Mark II)

Ruger MK III (Ruger Mark III)

Ruger MK IV (Ruger Mark IV)

Ruger P85

Ruger P90-95

Ruger P97

Ruger 22/45

This mount doesn't fit:

Ruger P89

Material: 7075 Aluminum

Coating: Matte Black Hardcoat

Overall Length: 1.604"

Overall Width: .99"

Mounting Hardware: (2) 6-32 Button Head Screws, (2) 6-32 X 3/16 Set Screws

Red Dot Fitment:

Bushnell RXS-100

Crimson Trace CTS-1500

Holosun 407K*

Holosun 407k-GR

Holosun 507K*

Holosun 507k-GR

Holosun EPS-GR*

Holosun EPS-RD*

Holosun EPS-Carry-GR*

Holosun EPS-Carry-RD*

Jpoint

Leupold Delta Point Pro

Optima

Redfield Accelerator

Shield RMS

Shield RMSc

Shield SMS

Sig Romeo Zero