SOG knives have been the gold standard of American-made duty knives for years. With robust materials and innovative designs that provide users with guaranteed performance, SOG knives just work. The Pentagon knife series has continued to grow over the decades. In this SOG Pentagon OTF Knife review, we’ll discuss pros, cons, specs and more.
The original Pentagon was designed as a dagger-bladed fixed-blade knife to be used as a backup weapon for soldiers and law enforcement. As the popularity of these knives increased, SOG produced variants in size and blade design to meet the needs of its users, from covert and plain clothes work to everyday carry. The newest iteration of the Pentagon lineup is the Pentagon OTF, a compact and combat-ready automatic knife.
What is an OTF Knife?
OTF stands for “Out the Front”. This refers to automatic and gravity knives that use their handle as a sheath. These knives feature a front-facing blade deployment that allows for lightning-fast opening with minimal effort.
One advantage of OTF knives is they can be used ambidextrously. With no top or bottom, the knife can be deployed with either hand and with whatever finger is available depress the “go button”.
The Pentagon OTF is commonly known as a switchblade. While this allows for fast deployment of the blade, it also limits who can carry it. SOG has a list of states that they will and will not ship to based on the laws in those states. As always, doing your homework on your state’s laws can be the difference between safety and a fine.

The Blade
The SOG Pentagon OTF is crafted with an unwavering commitment to excellence. Following the design of SOG’s legacy models, the OTF features a 3.75-inch dagger-style blade is constructed from top-tier CPM S35VN steel. The steel was developed by American forge Crucible Industries and master bladesmith Chris Reeve. This premium knife steel is designed specifically for knife making, offering a combination of toughness, edge retention, and corrosion resistance that has made it a top choice for high-end knife makers worldwide. For more information on CPM S35VN, you can see our in-depth look at the steel here.
The Pentagon’s non-serrated, flat grind blade ensures efficient cutting and snag-free deployment. The black matte titanium nitride finish not only adds a stylish touch but also provides enhanced corrosion resistance and less reflection than a high-luster finish.
The Body
Whether you’re right-handed or left-handed, the Pentagon OTF will accommodate your needs. The thumb slide opener allows for effortless, one-handed deployment, making it a reliable tool in high-pressure situations. The tip-down pocket clip ensures secure and discreet carrying, allowing you quick access to the knife whenever you need it.
Built to withstand the rigors of use, the Pentagon OTF features a sturdy aluminum handle that offers a comfortable and secure grip. The Pentagon’s aluminum frame is powder-coated to resist corrosion and improve grip. Users can choose from FDE or black. The frame is also scalloped to reduce the overall mass of the sizable knife and accommodate gloved hands. The steel frame/liner adds extra strength to the handle, ensuring it can endure heavy use and challenging conditions. Handling this knife, it is apparent that it’s not just a pocket knife; it’s a tool you can trust your life with.
The Mechanism
The “go button” on the Pentagon OTF works as both a locking mechanism to keep the blade closed and ready as well as to keep it open. The unique textured elongated button features two hills, allowing the user to gain purchase on the button from the back, center, or front of the button. This lock system is “double action,” as Eugene Neilson of Spotterup.com calls it, allowing for the lock to remain open long enough for the blade to extend or retract fully. The lack of proper dwell time of other OTF knives has been a shortcoming that seems to have been addressed with the Pentagon’s dynamic lock system.

Locking Feature
The Pentagon OTF’s dynamic locking feature results in incredible lockup with nearly no play in the bade or “rattle”. SOG’s Dynamic Locking System ensures the blade moves quickly to the open or closed position. When it’s there, it’s held firmly in place in a secure, reliable and confident lock-up.” ~sogknives.com
Made in the USA
SOG takes pride in producing its knives in the USA, ensuring that each product meets the highest standards of quality and craftsmanship. When you choose the Pentagon OTF, you’re supporting American manufacturing and enjoying a knife that’s a cut above the rest.
Conclusion
The SOG Pentagon OTF Knife is a true embodiment of precision, performance, and reliability. With its impressive specifications, user-friendly design, rugged durability, and versatile functionality, it’s the perfect companion for both tactical professionals and everyday carry enthusiasts. Crafted with the utmost care and precision in the USA, this knife represents the pinnacle of American knife manufacturing. So, whether you need a dependable tool for your daily tasks or a reliable companion for the high stress situations, the SOG Pentagon OTF Knife is the answer. Elevate your EDC game with the SOG Pentagon OTF, and experience the difference that SOG calls Only The Finest.
Specs
- Overall Length:9.00″
- Blade Length:3.75″
- Cutting Edge:3.75″
- Blade Width:0.75″
- Blade Thickness:0.13″
- Blade Material:CPM S35VN
- Blade Style:Dagger
- Blade Grind:Flat
- Finish:Black
- Edge Type:Plain
- Handle Length:5.25″
- Handle Width:1.25″
- Handle Thickness:0.59″
- Handle Material:Aluminum
- Color:Black
- Frame/Liner:Steel
- Weight:6.70 oz.
- User:Right Hand, Left Hand
- Pocket Clip:Tip-Down
- Knife Type:Automatic
- Opener:Thumb Slide
- Brand:SOG
- Model:Pentagon OTF
- Model Number:15-61-01-57
- Country of Origin:USA
