I worked for an outfitter in nw manitoba for 16 years we took over 300 bears . I would never use a 2 blade head. I have shot bear with 2 blades, 4 blades and 3 blade, you need to find the animal after you shoot it, you need a blood trail you may get one with 2 blade and you may not, better chance with multiable blade of having a trail and better chance of finding your animal with a marginal hit. Penetration is not a problem with bears unless you hit the shoulder bones and then it doesnt matter what broadhead you use .I seen so many things happen,many shoulder shots, head shots, even ears shot off and complete misses at 10 yards. People get very excited when the time comes to draw the bow. Probably more bears are wounded than any other animal that is bowhunted. The worst thing I seen in broadheads was the long skinny single bevel, high loss rate, a hole that you could barely slide a nickle in and plugged with fat. A snuffer ,woodsman ,vpa, razorhead or similar multi-blade works best.