Comparison

E4 Flex vs RubberSource

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

Head to head

E4 Flex

Manage E4 Flex with BLE

Free

📊 Productivity

★ 5.01 ratingsView app →

About

E4 Flex

This app enables field technicians to connect to and manage E4 Flex readers via Bluetooth Low Energy. It allows for sending commands and receiving responses, facilitating configuration and testing of the readers.

Highlights

Connect to E4 Flex readers via BLE
Send commands to readers
Receive responses from readers
Configure E4 Flex readers
Test E4 Flex readers

Read full description

The E4 Flex allows users to find and connect to E4 Flex readers in close proximity using the BLE interface. The user can send commands and receive responses as if they were connected using the typical serial or network connect. This app is a new tool for field technicians to configure and test the E4 Flex Reader.

About

RubberSource

Features

Read full description

RubberSource provides a complete lining system, technical service, material, cement, and repair material. This slide rule contains chemical resistance ratings that have been developed from various sources. The purpose of this data is to help you narrow the choice of materials when selecting the proper liner for your specific needs. For the best recommendations on specifying all your rubber linings, please check with RubberSource’s technical department. Allow a safety margin beyond the most extreme conditions you expect. Wear due to abrasion, impact, and temperature extremes.

Screenshots

E4 Flex3 screens

RubberSource4 screens

Verdict

The call

The clearest difference is update cadence: RubberSource at every 3 weeks against E4 Flex's every 21 months. 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

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

E4 Flex ships an update every 21 months, RubberSource every 3 weeks. The most recent releases landed on September 16, 2026 and September 30, 2026 respectively.

Scorecard1 real difference · 8 level

E4 Flex versus RubberSource: the parameters behind the verdict, then further details
Parameter	E4 Flex	RubberSource
Price	Free	Free
Rating	5.0 (1 ratings) — better	—
Number of ratings	1 — better	—
Update frequency	Every 21 months	Every 3 weeks — better
Ads	No	No
In-app purchases	No	No
Monetization	Free	—
Devices	iPhone, iPod	iPhone, iPad, iPod — better
Requires iOS	13.1	12.3 — better
Further details — not scored
Size	1 MB	23 MB
Age rating	4+	4+
Developer	Paul Hamel	Avanaire Design, LLC

In-app purchases

None

E4 Flex

No in-app purchases

None

RubberSource

No in-app purchases

Questions

Is E4 Flex free?

E4 Flex is free to download, with no in-app purchases.

Is RubberSource free?

RubberSource is free to download, with no in-app purchases.

Do E4 Flex or RubberSource have ads?

Neither E4 Flex nor RubberSource shows ads.

Which is updated more often, E4 Flex or RubberSource?

E4 Flex ships an update every 21 months, and RubberSource every 3 weeks. Most recently, E4 Flex was updated on September 16, 2026 and RubberSource on September 30, 2026.