688 H ZZ W4 EZO 8x16x4 mm - Stainless Steel Miniature Deep Groove Ball Bearing

688 H ZZ W4 EZO 8x16x4 mm - Stainless Steel Miniature Deep Groove Ball Bearing

EZO 688 H ZZ W4 is a miniature single-row deep groove ball bearing with dimensions 8x16x4 mm. It has an 8 mm bore, 16 mm outside diameter and 4 mm width. The H designation identifies the stainless steel version, ZZ indicates metal shields on both sides, while W4 identifies an additional special EZO specification.

Technical data

EZO 688 H ZZ W4 dimensions

Basic dimensions:

d: 8 mm
D: 16 mm
B: 4 mm

Complete dimensional specification:

8x16x4 mm

The compact radial cross-section makes the 688 series suitable for miniature bearing arrangements requiring an 8 mm bore with limited installation space.

What does 688 H ZZ W4 mean?

The complete designation identifies the specific EZO bearing configuration:

688 - bearing series and size with dimensions 8x16x4 mm.

H - identifies the stainless steel version in this EZO bearing family.

ZZ - metal shields on both sides of the bearing.

W4 - additional EZO special specification. The W4 suffix should be retained when identifying or selecting a replacement.

The full designation 688 H ZZ W4 is therefore important for correct product identification.

Bearing construction

EZO 688 H ZZ W4 is a miniature single-row deep groove ball bearing consisting of:

• inner ring,
• outer ring,
• balls,
• cage,
• metal shield on one side,
• metal shield on the opposite side.

Its deep raceway geometry is designed primarily for radial loads and can also accommodate axial loads in both directions within the operating limits of the bearing arrangement.

Stainless steel H version

The H designation identifies the stainless steel version of this EZO bearing.

Compared with a standard bearing-steel version, stainless steel provides increased resistance to corrosion. However, stainless construction should not be interpreted as complete resistance to every chemical substance or corrosive environment.

Operating conditions, lubricant and exposure to moisture or aggressive media should always be considered when selecting the bearing.

ZZ metal shields

The ZZ suffix indicates metal shields on both sides.

The shields help:

• protect the raceways and rolling elements against contamination,
• retain lubricant inside the bearing,
• provide a low-friction closure compared with contact-type sealing solutions.

ZZ shields should not be confused with elastomeric 2RS seals.

What does W4 mean?

W4 is an integral part of the complete EZO 688 H ZZ W4 designation.

Without confirmed manufacturer documentation defining W4 for this exact bearing version, it should not be interpreted as a specific internal clearance, precision class, lubricant or cage material.

For a technically safe product specification, it should therefore be stated as:

W4 - special EZO specification.

688 H ZZ W4 vs 688 H ZZ

Both versions have the same basic dimensions of 8x16x4 mm, but the W4 suffix identifies an additional specification.

Therefore, 688 H ZZ W4 should not automatically be replaced by 688 H ZZ without confirming the requirements of the original bearing arrangement.

This is particularly important in miniature and precision mechanisms.

688 H ZZ vs 688 ZZ

The principal difference is the material version.

688 H ZZ - EZO stainless steel version.

688 ZZ - standard material version.

Although the basic dimensions may be identical, the material specification and resulting operating characteristics are not necessarily the same.

Selection and interchangeability

Before selecting a replacement, verify:

• complete designation 688 H ZZ W4,
• EZO manufacturer,
• dimensions 8x16x4 mm,
• stainless steel H version,
• ZZ metal shields,
• W4 specification,
• required internal clearance,
• required precision,
• lubrication conditions,
• operating load and speed.

Matching dimensions alone do not guarantee complete interchangeability.

Installation and operation

Miniature bearings require clean and precise installation.

When mounting the bearing onto a shaft, force should be applied to the inner ring. When pressing it into a housing, force should be applied to the outer ring.

Mounting force should never be transmitted through the balls, and direct pressure on the ZZ metal shields should be avoided.

Alternative designations and reference formats

• EZO 688 H ZZ W4
• 688 H ZZ W4 EZO
• EZO 688HZZW4
• 688HZZW4 EZO
• 688 H ZZ W4 8x16x4
• EZO 688 H ZZ W4 8x16x4
• 688HZZW4 8x16x4

The complete manufacturer designation should be retained whenever possible.

FAQ - EZO 688 H ZZ W4

What are the dimensions of EZO 688 H ZZ W4?

The bearing measures 8x16x4 mm, with an 8 mm bore, 16 mm outside diameter and 4 mm width.

What type of bearing is EZO 688 H ZZ W4?

It is a miniature single-row deep groove ball bearing.

What does H mean?

H identifies the stainless steel version in this EZO bearing family.

What does ZZ mean?

ZZ indicates metal shields on both sides of the bearing.

What does W4 mean?

W4 identifies an additional EZO special specification. Without confirmed documentation for this exact version, it should not be interpreted as a specific clearance, lubricant, precision class or cage material.

Is EZO 688 H ZZ W4 a stainless steel bearing?

Yes. The H designation identifies the stainless steel version.

Can 688 H ZZ replace 688 H ZZ W4?

Not automatically. W4 forms part of the complete specification and should be verified before selecting a replacement.

Does ZZ mean rubber seals?

No. ZZ indicates metal shields. Elastomeric seals are a different closure design.

EZO 688 H ZZ W4 - key information

EZO 688 H ZZ W4 8x16x4 mm is a miniature single-row stainless steel deep groove ball bearing with metal shields on both sides. It has an 8 mm bore, 16 mm outside diameter and 4 mm width. W4 identifies an additional EZO specification and should be retained when selecting an equivalent bearing.

Available from simmering.pl, a specialist supplier of bearings and industrial components. Stock in Poland with worldwide shipping.