KastKing Speed Demon Pro Lithium-Ion Electric Fillet Knife Review
A cordless electric fillet knife at less than half the price of BUBBA's, with a claimed 1 hr 40 min runtime per charge: a good fit for freshwater anglers.
Last updated October 17, 2026Our score: 8.0/10
Amazon: 4.3 out of 5 stars from 549 ratings (checked October 17, 2026)
$71.99Price checked October 17, 2026. May have changed.
Pros and cons
Pros
Cordless for less than half the price of premium brands
Maker claims up to 1 hr 40 min per charge, with a 4-step battery gauge
7" Finesse and 9" Talon flex blades included
Slim, well-organized carry case
Cons
Spare batteries aren't sold separately (the $129.99 Guide pack includes two)
Lower Amazon rating (4.3) than BUBBA's cordless knife, with more mixed reviews
Some buyers find the blades fiddly to click in
No stiff blade for heavy saltwater fish
Who is the KastKing Speed Demon Li-Ion for?
Buy it if: Freshwater anglers who want a cordless electric knife without spending premium money.
Skip it if: Saltwater anglers cleaning large, heavy-boned fish.
Crappie
Walleye
Bass
Perch
Our review
KastKing's Speed Demon Pro gives you a cordless electric knife for less than half the price of BUBBA's. The 2500 mAh lithium-ion pack (18650 cells) is rated by KastKing at up to 1 hour 40 minutes of continuous use, and a gauge shows 100, 75, 50 or 25% charge. The runtime is the manufacturer's figure, not ours.
This listing is the Angler Pack: a 7-inch Finesse blade and a 9-inch Talon flex blade in 420 stainless with a titanium vapor-deposition coating, one battery, a charger and a slim EVA case. Note that battery packs aren't sold separately, so if you want a spare, buy the Guide Pack (4 blades, 2 batteries, $129.99 when we checked).
On Amazon, buyers most often praise the battery life, the sharp blades, the case and the value. Reviews are more mixed than for BUBBA: some say it performs poorly, and a few find the blades fiddly to install.
It's best suited to freshwater fish. If you mostly clean large saltwater fish, BUBBA's kit with its stiff 12-inch blade is the better tool.
Is the blade the right size?
Here’s where its 9-inch blade sits against typical fish sizes. See blade length by fish for more.
Panfish 4–6"Bluegill · Crappie · Perch
Mid-size 6–7.5"Walleye · Bass · Trout
Big fish 7.5–9.5"Salmon · Redfish · SnapperThis knife: 7" / 9" blades
Giants 9.5–12"+Tuna · Halibut · Mahi
Typical blade length (inches) for each fish size.
How we evaluated it
This review is based on the manufacturer’s specifications, the Amazon listing and patterns in verified buyer feedback, compared against the other knives we cover. We haven’t lab-tested it. Read our method.
The best electric fillet knife for most people: cordless, with four blades from 7 to 12 inches, so one kit covers panfish limits up to large saltwater fish.
7" / 9" / 12" blades
Medium flex
Electric
Saltwater-ready
Crappie limits
Salmon
Snapper
Mahi
$169.00Price checked October 17, 2026. May have changed.
Budget cordless filleting with two batteries, from panfish to walleye
The best budget cordless electric fillet knife: two batteries, a fast charger and 8" flex plus 10" stiff blades for about $70, with some durability concerns.
8" / 10" blades
Medium flex
Electric
Walleye
Crappie
Perch
Snapper
$69.99Price checked October 17, 2026. May have changed.