Bear OPS Bear Song IV Butterfly Knife Aluminum (4.38" Black) B-400-B

MSRP: $151.99
Our Sale Price: $89.95!
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Item #BHQ-13030


  • Overall Length:9.75"
  • Blade Length:4.375"
  • Blade Material:1095
  • Hardness:58-60 RC
  • Blade Style:Spear Point
  • Blade Grind:Hollow
  • Finish:Black
  • Edge Type:Plain
  • Handle Length:5.375"
  • Handle Material:Aluminum
  • Color:Gray
  • Weight:4.48 oz.
  • Knife Type:Butterfly
  • Brand:Bear Ops
  • Model:Bear Song IV
  • Model Number:B-400-B
  • Country of Origin:USA
  • Best Use:Recreation
  • Product Type:Knife


The Bear Song IV butterfly knife is a collaboration between BladeRunnerS (BRS) and Bear OPS. It is a lightweight flipper that is designed to be your go-to everyday carry knife. The B-400 model features natural finished aluminum handles with stainless steel spacers and a swappable latch. The pivots have 304 bearing surfaces and phosphorus bronze washers. The ti black finished 1095 high carbon steel clip point blade has a double tang pin design for great performance.


Customer Reviews

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Curtis M.
Pin broke in literally one day, and it wasn't even heavy use. It did work very well though for the 2 or so hours it lasted. Fortunately bladehq replied to my email in a couple hours so I should be able to return it. I'm most likely going to invest in a more expensive knife.
Blade HQ response:
We're very sorry to hear about the trouble you're having. Have you contacted our customer service department yet ( We'd like to help you get this resolved. Thanks -BHQ
Do not buy any bear ops knife!
Jackson P.
Had this knife for about a week and barely carried or flipped it. I decided to flip it one day and after about 5 minutes a tang pin breaks. soon after the other one broke. I examined it and realized the tang pin was two pieces that screw together in the middle of the tang. I simply loctited the screw and went back to flipping. The knife performed well UNTIL the tang pins broke again, but this time they didn't unscrew, the screw just snapped. VERY cheap construction. I have had three dollar comb trainers last longer than this. Also the latch screw came with red loctite so i couldn't get the latch off. Also came dull as a trainer, this couldn't cut my fingers even if i wanted it to. The knife itself has handles that are way too thick and square(fanning and transfers were impossible), the latch doesn't hold the knife open or closed, and there was WAY too much handleplay. I never thought i would say this, but i wish i had bought a qtrmstr.
Good Company & Customer Service!
Dennis C.
I have had this knife for 1 month and is not functional. This is my first butterfly knife. I learned a couple of tricks with very light flipping and the tang pins came off. They broke at the center and do not go back together. Also the handle has bent so bad that the lock constantly catches when opening. I have submitted an email to Bear & Son regarding this and waiting for a response back. Will update based on that response.

Update: 7-30-2016 - Received a response back regarding my issues and was sent two (2) new sets of pins for my knife. Did not have to jump through any hoops other than sending pics of my knife and the damaged pins. New sets of pins were mailed out that day. I have them installed and knife functions great. It is never about the problem you have with a product but how the company handles the issue. Bear and Sons was great in taking care of the issue. This is a great company who backs their products! I will continue to purchase items from Bear and Sons! If I could give a half a star I would give them a 4.5 out of 5. Thank you Bear and Sons!
Blade HQ response:
We're very sorry to hear about the trouble you're having. Have you contact our customer service department yet ( We'd like to help you get this resolved. Thanks -BHQ
I was sent a defective knife; service is very frustrating.
Matt R.
I received the knife in such an unflippable condition (out of the box, it would not flip. I had to use two hands from the massive tension.). I was forced to adjust it, and then quickly noticed that it needed loctite badly. I went out and bought loctite and refrained from flipping it until I could put the thread locker on, and in the meantime went to Disneyworld. When I came back, I took out the pivot screws to put loctite in and very quickly noticed that the top upper quarter of the pivot barrel is chipped and missing. I called Bear and Son about this problem and was essentially told by the company president himself that it was probably my fault for taking apart the knife (Adjusting the screws and putting in required loctite to make the knife usable). I asked if I could simply be sent a replacement pivot and was refused. The only option I was given is to send it in to Alabama and pay around $10 for shipping for them to "fix" the knife, (I.e. replacing a pivot barrel that I'm apparently too incompetent to replace myself as the president suggested.) I was also told that I'm lucky that they are willing to fix their faulty product at all, as they said all other companies would say that putting loctite on the product would void warranty. Benchmade would say that? They SUGGEST putting loctite on their balis, and mention in the warranty papers under regular knife care; this company obviously isn't Benchmade, but that remark was unbelievable for me. Again, a broken pivot barrel is "probably" my fault. I won't be sending in the knife to be repaired, as it honestly isn't worth an extra $10. This is also most likely to be the last Bear and Son product I will ever buy. P.s. the operator who I spoke to in the beginning of the phone call before I asked to speak to the president himself relayed the message as "He took his knife apart; now he needs us to put it back together", that's what the company president told me was said to him. Maybe your experience with this knife will be better. The knife itself is actually decent; it flips alright, if you happen to get one that isn't impaired. Lol