O vs FCM IoT
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
O
This app helps users calculate O-Ring dimensions and find compatible materials for their applications. It provides recommendations based on ISO standards and supports both metric and inch measurements.
- O-Ring housing calculation
- O-Ring size recommendations by ISO standard
- Quick search by national/international standards
- O-Ring tolerance calculation
- Metric and inch unit switching
- Chemical compatibility check
- Integration of Trelleborg Sealing Solutions Videos
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The Trelleborg Sealing Solutions O-Ring App calculates O-Ring dimensions by simply entering installation specifications for your application in metric or inch. In addition, the App recommends O-Ring sizes according to ISO 3601 so you know exactly which part you need. Features at a Glance: - O-Ring Housing: After entering the bore or rod/shaft diameter, you will receive an O-Ring recommendation and O-Ring housing calculation according to the recommendations of ISO 3601 - O-Ring Quick Search: offers the selection of O-Ring nominal sizes according to the following national/international standards: ISO 3601-1 Class B (International), ISO 3601-1 Class A (AS 568, USA), NFT 47-502 (France), JIS B 2401 (Japan) SMS 1586 (Sweden) - Tolerances: calculation of O-Ring tolerances according to ISO 3601-1 Class B and Class A - Switch between metric and inch - Chemical compatibility check: find out which materials are compatible with the media used in your application. - Integration of Trelleborg Sealing Solutions Videos
FCM IoT
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eFMS is short of electronic facility management system, focus on company’s EHS, facility and admin management.This is a software with WEB dynamic template and workflow engine, provides customer one-stop SaaS on cloud platform, user can access it via H5, Webpage, APP. Free configuration of permissions, can be used on the same platform in multi-sites and factories, or can be deployed privately.
Screenshots
Verdict
The clearest difference is update cadence: FCM IoT at every 3 weeks against O's every 3 months. O's advantage is iOS requirement (12.1 vs 15.0). 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 3 months, FCM IoT every 3 weeks. The most recent releases landed on October 23, 2026 and October 5, 2026 respectively.
| Parameter | O | FCM IoT |
|---|---|---|
| Price | Free | Free |
| Rating | 3.8 (5 ratings) — better | — |
| Positive reviews | 83.3% of reviews | — |
| Number of ratings | 5 — better | — |
| Update frequency | Every 3 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.1 — better | 15.0 |
| Further details — not scored | ||
| Size | 26 MB | 96 MB |
| Age rating | 12+ | 4+ |
| Developer | Trelleborg Sealing Solutions | 苏州曼捷科智能科技有限公司 |
In-app purchases
O
No in-app purchases
FCM IoT
No in-app purchases









