The Stanley 10-789 FATMAX Xtreme Twin Blade Retractable Knife is a retractable utility knife built for users who need to move between different cutting tasks without carrying multiple knives. This is a utility knife designed for general cutting, trimming, and jobsite material prep. Model Number: 10-789. The big advantage here is simple: you get a twin blade setup in one body, so you can alternate between loaded blades instead of stopping to swap knives.

The twin blade design is what makes this knife different from a standard single-blade utility knife. You can keep one blade set up for one task and the second for another, which is especially useful when you are moving between straight cuts and hook-blade work. Stanley also uses interlocking blade sliders so only one blade is extended at a time, which keeps operation straightforward and adds a practical layer of safety during use.

Blade changes are quick thanks to the InstantChange feature. When a blade gets dull, you can replace it in seconds without turning the job into a bench project. That matters on a real workday, because utility knives do not save time when the blade-change process is slow. This knife also includes onboard blade storage, so spare blades stay with the tool instead of getting lost in a pouch or truck drawer.

In hand, this Stanley FATMAX utility knife is built more like a serious daily-use tool than a disposable cutter. The metal body gives it solid structure, and the rubber grips help reduce hand fatigue and cut down on slipping when your hands are dusty or you are making repeated pulls. The overlap nose adds durability up front, where utility knives usually take the most abuse.

From the spec side, the knife is retractable, uses standard and hook utility blades, and has tool-free blade change. Overall length is 6-7/8 inches, so it is long enough to feel secure in the hand without being oversized for pouch carry. Stanley lists blade storage capacity at 5 pieces in the handle, while the product copy also highlights easy-access storage for up to 9 blades and a total working/storage capacity of 11 when including the two loaded blades. Either way, the point is the same: this knife is built to keep extra blades close at hand.

This is a good fit for contractors, remodelers, flooring installers, roofers, warehouse crews, and serious DIY users who go through blades regularly and want one knife that can handle more than one cutting setup. If you are the kind of user who normally carries a standard utility knife and a second knife with a different blade, the Stanley 10-789 FATMAX Xtreme Twin Blade Retractable Knife is the cleaner solution.

One Knife That Actually Replaces Two

The Stanley 10-789 FATMAX Xtreme Twin Blade Retractable Knife makes a lot of sense for anyone who is tired of carrying multiple cutters just to stay efficient.

• Who it's for: Pros and serious DIY users who switch between blade types and want a tougher everyday utility knife.
• Why it stands out: The twin-blade setup, tool-free blade changes, and solid metal body solve real jobsite annoyances instead of adding gimmicks.
• Worth knowing: The exact onboard blade storage count varies by source, but all sources agree this knife stores spare blades and ships ready to use with both a standard blade and a hook blade.

• Is this a retractable utility knife? Yes. Stanley lists the 10-789 as having a retractable blade.
• Can it use more than one blade style? Yes. It is designed for standard and hook utility blades.
• Does it have tool-free blade changes? Yes. Stanley lists this knife as having tool-free blade change with its InstantChange feature.
• Does the handle store extra blades? Yes. The knife has onboard blade storage for quick access to spare blades.