Both wrenches are for 1-7/8" nuts and fit all Catalinas using a 1" prop shaft that we are aware of.
There may be early boats built before any detailed records were kept that use a different size. To be certain they are correct for your boat, you may want to measure your stuffing box before ordering.
Why our wrenches work:
• Short handles are easy to maneuver in the confines of the small spaces behind the transmission
• Thin wall pattern fits the thin jam nut of the stuffing box
• Trim jaws will fit between the stuffing box and the hull in nearly any boat
• Perfect 30 degree offset allows you to flip the wrench over to shift the position of the handle in the bilge
• Real wrenches don't break when you look at them
Why standard wrenches don't work:
• Crescent wrench: Jaws too large, handle too long, jaws too wide to fit the narrow jam nut
• Standard end wrench: When jaws are large enough for the nut, the handle is much too long to maneuver easily
• Monkey wrench: Jaws are at the wrong angle to fit into the bilge
• Pipe wrench: Jaws much too large and wide, teeth damage the stuffing box
• El Cheapo adjustable packing nut wrench sold by our competitors: Don't have any children aboard when using this wrench as you will be swearing a blue streak when it breaks and you bloody your knuckles against the rough fiberglass in the bilge!
Caution!
Never use only one wrench! There is only a piece of rubber hose holding the stuffing box to the hull. If you honk on the nut with only one wrench you are trying to twist the fitting within the hose. You will at least break the seal between the hose and the fitting. At worst you will damage the stuffing box hose and cause a substantial leak. Just hope someone is within ear shot when you do!
There is a different stuffing box used on very early Catalinas (early '80's) that used two different wrench sized, neither of which are 1-7/8". 
