O vs CDHM Tester
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.
CDHM Tester
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The LERO CDHM Series Portable Hydraulic Tester can be used as a stationary or portable tester for hydraulic system diagnostics, and analysis of the prognostic health of a hydraulic system.Testing for Pump, Motor, Cylinder and Valve. CDHM数字式液压测试仪，用于液压系统故障分析和系统的良性循环评估,可通过测试液压泵，阀，油缸的流量、温度和压力来判断. Flow/流量范围:Up to 800 lpm Pressure/耐压范围:Up to 420 bar Flow Direction/测试方向 :directional as arrow/箭头所示方向 Loading Valve(optional)/带加载阀(可选) Wifi function(optional)+App/自带Wifi功能(可选)+App
Screenshots
Verdict
The clearest difference is update cadence: CDHM Tester at every 5 weeks against O's every 11 months. CDHM Tester also leads on iOS requirement (12.0 vs 16.0). On price, ads, in-app purchases and device support 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, CDHM Tester every 5 weeks. The most recent releases landed on October 12, 2026 and October 5, 2026 respectively.
| Parameter | O | CDHM Tester |
|---|---|---|
| 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 5 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone | iPhone, iPod — better |
| Requires iOS | 16.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 47 MB | 30 MB |
| Age rating | 4+ | 4+ |
| Developer | GE MAO RUBBER INDUSTRIAL CO., LTD. | 深圳雷诺智能技术有限公司 |
In-app purchases
O
No in-app purchases
CDHM Tester
No in-app purchases
