Comparison

CHALLNA vs 레트로 시계

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

CHALLNA

This app helps you achieve precise timing for critical online events by displaying accurate server time, accounting for network latency. It offers one-touch presets for popular sites, countdown timers, and practice modes to improve your reaction speed for ticket sales, course registrations, and limited drops.

Highlights
  • Millisecond precision synchronization
  • One-touch server presets
  • Intuitive countdown timers
  • Click practice mode
  • Smart reminders and schedule registration
  • Direct site access
  • Dynamic Island support
Features
Read full description

■ 0.01 Seconds Make All the Difference. Have you ever missed out on popular concert tickets, course registrations, or limited-edition drops by a split second? Don’t rely on your phone’s local time. Check the "Real Server Time" of the site itself. 'CHALLNA' will drastically increase your success rate. ■ Why CHALLNA? (Key Features) 1. Millisecond(ms) Precision Synchronization We do more than just fetch server time. CHALLNA calculates network latency (RTT) and average transmission deviations in real-time to correct any errors. Find the "true" 0.01 second with Korea’s highest level of precision. 2. One-Touch Server Presets Interpark, YES24, Melon Ticket, and even major university registration sites! No need to type addresses manually. Simply search to instantly register and track your desired server. 3. Intuitive Countdown & Target Setting Set your goal time and watch the countdown in real-time down to the millisecond. Stay perfectly prepared for that high-pressure moment right before the opening. 4. Click Practice for Real-World Reflexes Theory is different from practice! Use the built-in 'On-the-Dot Click Practice' to check your reaction speed and master the feeling of clicking at exactly 0.00 seconds. 5. Smart Reminders & Schedule Registration (HOT!) Register your important ticketing or course registration schedules. We’ll make sure you’re ready with custom notifications before your target time, even in your busy daily life. 6. Direct Site Access Why check the time and switch apps separately? CHALLNA provides direct outlinks to the sites, shortening your access time to the absolute minimum. 7. Dynamic Island Support Keep tracking the time via Dynamic Island even while moving to the ticketing site, ensuring you never miss the countdown. (Available on iPhone 14 Pro and later models) ■ Highly Recommended For: • Concert fans tired of losing out in "Blood-keting" (bloody ticketing). • Students desperate to secure popular university courses. • Anyone needing perfect timing for holiday train bookings or limited drops. • Perfectionists who won't settle for even a 0.01-second error. ■ Please Note: • Minor errors may occur depending on network conditions. We recommend using a stable Wi-Fi, 5G, or LTE environment. • For the best results, be sure to use the 'Click Practice' feature in advance! Download 'CHALLNA' now and experience the miracle of 0.01 seconds!

About

레트로 시계

Features
Read full description

심플한 레트로 LCD 시계입니다. 7세그먼트 디스플레이로 시간을 보여주고, 날짜와 날씨도 함께 표시됩니다. 화면이 꺼지지 않아 탁상시계로 딱 좋습니다. • 5가지 LCD 테마 (게임보이, 네온, 앰버, 블루, 레드) • 현재 위치 기반 날씨 표시 • 날짜 및 요일 표시 • 가로 모드 전체화면 • 광고 없음, 추적 없음

Screenshots

CHALLNA4 screens
레트로 시계3 screens

Verdict

The call

The clearest difference is iOS requirement: 레트로 시계 at 13.0 against CHALLNA's 16.6. On price, update cadence, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

CHALLNA ships an update every 2 weeks, 레트로 시계 fortnightly. The most recent releases landed on October 12, 2026 and October 1, 2026 respectively.

Scorecard1 real difference · 7 level
CHALLNA versus 레트로 시계: the parameters behind the verdict, then further details
ParameterCHALLNA레트로 시계
PriceFreeFree
Positive reviews100.0% of reviews—
Update frequencyEvery 2 weeks — betterFortnightly
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS16.613.0 — better
Further details — not scored
Size38 MB15 MB
Age rating4+4+
DeveloperRYNYULYOUNGJOO KIM

In-app purchases

None

CHALLNA

No in-app purchases

None

레트로 시계

No in-app purchases

Questions

Is CHALLNA free?
CHALLNA is free to download, with no in-app purchases.
Is 레트로 시계 free?
레트로 시계 is free to download, with no in-app purchases.
Do CHALLNA or 레트로 시계 have ads?
Neither CHALLNA nor 레트로 시계 shows ads.
Which is updated more often, CHALLNA or 레트로 시계?
CHALLNA ships an update every 2 weeks, and 레트로 시계 fortnightly. Most recently, CHALLNA was updated on October 12, 2026 and 레트로 시계 on October 1, 2026.

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