O vs KL500A
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
O
This app provides a comprehensive offline tool for selecting standard rubber seal sizes, including O-Rings, X-Rings, and Back-Up Rings. It offers dimension searches, housing calculations for various sealing applications, and supports multiple international standards in both metric and imperial units.
- Offline standard rubber seal size selection
- Search for O-Ring, X-Ring, and Back-Up Ring sizes
- O-Ring housing calculations for sealing applications
- Supports multiple international standards (AS568, METRIC, JIS, etc.)
- Metric and Imperial unit support
- Substitutable O-Ring size suggestions
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GMORS O-Ring Master is the completed tool for standard rubber seal sizes. When you use this APP, you don't need to have internet and catalog. Except O-Ring sizes, it also includes the search functions of X-Ring and Back-Up Ring. Otherwise, you can also use O-Ring Housing to choose suitable O-Ring in your application. Main functions are as follows: Dimension Search：O-Ring, X-Ring and Back-Up Ring. - MM and Inch are both available. - Full standard O-Ring series: AS568, BS 4518, GB/T 3452.1, JIS B2401 P, JIS B2401 G, JIS B2401 S, JIS B2401 V, SMS 1586 and METRIC. - Collocated Back-Up for AS-568 O-Ring. - Substitutable O-Ring sizes within tolerance are available. O-Ring Housing： Piston Sealing、Rod Sealing and Face Sealing. - MM and Inch are both available. - Support calculation for both Static and Dynamic sealing applications (Face sealing is with static calculation only). - Up to 7 O-Ring standards ( AS568, METRIC, JIS B2401 P/G/S/V, JASO F404, GB/T 3452.1, BS 4518 and SMS 1586) for most of size requirement of different groove design.
KL500A
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KL500 A系列电压电流表是一款能测量电压、电流、功率、充放电容量、瓦时、时间等多种物理参数的新型库仑计， 同时也可以设定参数实现过压保护、欠压保护、过流保护、过功率保护、过温保护及限时保护等多种保护功能。 该仪表能够自动识别电流的方向，并且对电池容量可以进行实时监控且采用彩色液晶显示被测数据，显示信息全面、人性化。 KL500A系列电压电流表在原有功能基础上加入电压电流曲线显示及导出的功能，同时可以使用手机 APP控制显示，也可以实时对固件进行更新升
Screenshots
Verdict
The clearest difference is update cadence: KL500A at every 4 weeks against O's every 11 months. KL500A also leads on device support (3 vs 1) and iOS requirement (11.0 vs 16.0). On price, 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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
O ships an update every 11 months, KL500A every 4 weeks. The most recent releases landed on September 26, 2026 and October 7, 2026 respectively.
| Parameter | O | KL500A |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 11 months | Every 4 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone | iPhone, iPad, iPod — better |
| Requires iOS | 16.0 | 11.0 — better |
| Further details — not scored | ||
| Size | 47 MB | 31 MB |
| Age rating | 4+ | 17+ |
| Developer | GE MAO RUBBER INDUSTRIAL CO., LTD. | 磊磊 周 |
In-app purchases
O
No in-app purchases
KL500A
No in-app purchases
