Best Performance 693CE 3x8x4mm Silicon Nitride Ceramic Bearings Precision Si3N4 Ball Bearing for Reels features:

Model: 693CE

Size: 3x8x4mm ceramic bearing

Ring Material: Si3N4 full ceramic

Ball Material: Si3N4 full ceramic

Cage: PEEK/PTFE

Lube: Dry lube

Sealed: Open

Package: Individual white box

693CE Full Ceramic Ball Bearings pictures as below:

Full Ceramic ball bearings: zirconia or silicon nitride? 

1. White ceramic bearings are made by ZrO2（Zirconium Oxide）

Zirconium Oxide ceramic ball bearing is mainly white.That is a very hard but also very light material. Boasting an excellent resistance to water, saltwater and many acids and alkalis, it also has a very wide temperature range and is suitable for use in high vacuum applications. 

2. Black ceramic bearings are made by Si3N4（Silicon nitride）

The silicon nitride ceramic ball bearing is mainly black. It has high strength, high wear resistance, high temperature resistance, corrosion resistance, acid and alkali resistance, and it has great electrical and magnetic insulation properties. It is one of the hardest materials in the world.

3. Zirconia ceramic balls have better wear resistance and corrosion resistance. At the same time, silicon nitride ceramic balls also perform well in terms of machining accuracy.

Full ceramic ball bearing applications:

Applications For Full Ceramic Bearings: MRI equipment, vacuum environments, semiconductor manufacturing, radiotherapy, food processing industrie, any extreme environment requiring non-corrosive, non-conductive or non-magnetic bearings.

Related Hybrid ceramic ball bearing popular sizes as following:

Ceramic Ball Bearing bore 2mm:  2x5x2mm, 2x5x2.5mm, 2x6x2.5mm, 2.5x6x...

Ceramic Ball Bearing bore 3mm: 3x6x2mm, 3x6x2.5mm, 3x7x3mm, 3x8x2.5mm, 3x8x3mm, 3x8x4mm, 3x10x4mm, 3x11x4mm

Ceramic Ball Bearing bore 4mm: 4x7x2mm 4x7x2.5mm, 4x8x2mm, 4x8x3mm,4x10x4mm, 4x11x4mm,4x13x5mm

Ceramic Ball Bearing bore 5mm: 5x8x2mm, 5x8x2.5mm, 5x9x3mm, 5x10x3mm, 5x10x4mm, 5x11x3mm, 5x11x4mm, 5x13x4mm

Ceramic Ball Bearing bore 6mm: 6x10x2.5mm, 6x10x2.5mm, 6x10x3mm, 6x12x4mm, 6x13x5mm, 6x15x5mm, 6x19x6mm

Ceramic Ball Bearing bore 7mm:7x11x3mm, 7x14x3.5mm, 7x14x5mm, 7x17x5mm

Ceramic Ball Bearing bore 8mm: 8x12x2.5mm, 8x12x3.5mm,8x14x4mm, 8x16x5mm

Ceramic Ball Bearing bore 9mm:  9x17x5mm, 9x20x5mm

Ceramic Ball Bearing bore 10mm: 10x15x4mm, 10x19x5mm, 10x20x5mm

Ceramic Ball Bearing bore 12mm: 12x18x4mm

Ceramic Ball Bearing bore 15mm: 15x21x5mm....

Inch/imperial sizes  Ceramic ball bearing : SR2C-2OS 1/8" x 3/8" x 5/32, SR156C-2OS 3/16" x 5/16" x 1/8, SR166C-2OS 3/16 x 3/8 x 1/8, SR168C-2OS 1/4"x3/8"x1/8..