Review · Ranked #15 overall

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)

9"
Check price on Amazon for KastKing Speed Demon Pro Lithium-Ion Electric Fillet Knife (opens Amazon in a new tab)
$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
4–6": Bluegill, Crappie, Perch; 6–7.5": Walleye, Bass, Trout; 7.5–9.5": Salmon, Redfish, Snapper; 9.5–12"+: Tuna, Halibut, Mahi0123456789101112Panfish4–6"BluegillCrappiePerchMid-size6–7.5"WalleyeBassTroutBig fish7.5–9.5"SalmonRedfishSnapperGiants9.5–12"+TunaHalibutMahiThis knife: 7" / 9" blades
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.

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