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Head-to-head buyer guide

Frizzlife SP99-NEW Under-Sink Water Filter vs RKIN Flash Undersink Reverse Osmosis System

Specs, prices, editor verdict, and who should buy which, compared side by side.

By Ryan · Founder
Updated Sep 27, 2026

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Quick verdict

Frizzlife SP99-NEW Under-Sink Water Filter (entry, $129.99) vs RKIN Flash Undersink Reverse Osmosis System (mid, $329.45). Different tools for different jobs (see the per-product details below).

Compared on 2 shared specs · same category (environment).

Frizzlife SP99 under-sink drinking water filter with faucet
Frizzlife

SP99-NEW Under-Sink Water Filter

Certified lead and chloramine reduction at the kitchen tap for about $130, with a 0.5-micron three-stage cartridge that installs in about 15 minutes.

PRICE
$129.99
View at Frizzlife →
RKIN Flash undersink reverse osmosis system with chrome lead-free faucet
RKIN

Flash Undersink Reverse Osmosis System

Undersink reverse osmosis usually starts around $500. The RKIN Flash lands a full RO system with a lead-free chrome faucet at $329.45, and it does it without a pump, a plug, or most of your cabinet.

PRICE
$329.45
View at RKIN →
The verdict

We have not scored these two head to head, so this page does not name a winner. The Frizzlife SP99-NEW Under-Sink Water Filter starts at $129.99 and the RKIN Flash Undersink Reverse Osmosis System at $329.45. The per-buyer recommendations below say who each one suits.

Side-by-side specs

SpecFrizzlife SP99-NEW Under-Sink Water FilterRKIN Flash Undersink Reverse Osmosis System
price$129.99$329.45
typeUnder-sink point-of-use drinking water filterUndersink reverse osmosis system (tank-based)
warranty1 year (extendable to 150% coverage via registration)1 year

Frizzlife SP99-NEW Under-Sink Water Filter also publishes: certifications, stages, filtration precision, flow rate, reduces, install

RKIN Flash Undersink Reverse Osmosis System also publishes: membrane, editions, operation, dimensions, faucet, filters

Who should buy which

Pick the Frizzlife SP99-NEW Under-Sink Water Filter if

City-water households, especially on chloramine-treated supplies, who want certified lead and chloramine reduction at the kitchen tap without the cost or complexity of reverse osmosis.

Skip if

You specifically need verified, certified PFAS/PFOA-PFOS reduction or remineralized RO water; step up to a reverse-osmosis system like the Frizzlife PD600-TAM3.

Pick the RKIN Flash Undersink Reverse Osmosis System if

Homeowners who want plumbed-in reverse osmosis at the lowest credible price and are comfortable with a weekend DIY install under the sink.

Skip if

You rent or cannot modify plumbing (RKIN's countertop units exist for exactly that), or you buy on independently confirmed certification listings, where Boroux leads this category.

Go deeper

FULL REVIEW
Read the Frizzlife SP99-NEW Under-Sink Water Filter review →
FULL REVIEW
Read the RKIN Flash Undersink Reverse Osmosis System review →

Frequently asked

Which is better, the Frizzlife SP99-NEW Under-Sink Water Filter or the RKIN Flash Undersink Reverse Osmosis System?

We have not scored these two head to head, so this page does not name a winner. The Frizzlife SP99-NEW Under-Sink Water Filter starts at $129.99 and the RKIN Flash Undersink Reverse Osmosis System at $329.45. The per-buyer recommendations below say who each one suits.

How much do they cost?

Frizzlife SP99-NEW Under-Sink Water Filter: $129.99. RKIN Flash Undersink Reverse Osmosis System: $329.45. Prices are verified against the manufacturer; check the live links for current pricing.

Who should buy which one?

Frizzlife SP99-NEW Under-Sink Water Filter: City-water households, especially on chloramine-treated supplies, who want certified lead and chloramine reduction at the kitchen tap without the cost or complexity of reverse osmosis. RKIN Flash Undersink Reverse Osmosis System: Homeowners who want plumbed-in reverse osmosis at the lowest credible price and are comfortable with a weekend DIY install under the sink.

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