To improve the sealing performance and O-ring life span, the battery compartment O-ring gland design has been changed from a crushed gland to a radial gland. Identification of the new radial cap can be made by observing the differences in the following table:
New: Radial Cap
- Radial gland design
- O-ring seals before computer turns on
- Sealing NOT dependent on torque applied to battery cap
- The compression on the O-ring is set by the gland groove diameter
- Petrel computer marked with “RC” under strap
- NERD computer marked with “RC” above battery compartment
SRI PART NUMBER: 21021-01
![](https://cdn.shopify.com/s/files/1/0838/3732/1530/files/blue-o-ring-1.jpg)
Note Screw Head Height and O-Ring Colour
![oring-groove-style-new](https://cdn.shopify.com/s/files/1/0838/3732/1530/files/oring-groove-style-new.jpg)
Note O-Ring Groove Style
![Machine Screw: Pan Head #4-40 x 1/4” Torx T10](https://cdn.shopify.com/s/files/1/0838/3732/1530/files/torx-new.jpg)
Machine Screw: Pan Head #4-40 x 1/4” Torx T10
Old: Crushed Cap
- Crushed O-ring gland design
- O-ring starts to seal as computer turns on
- Sealing dependent on torque applied to cap
- As the cap is tightened the O-ring is compressed into a cone shaped gland
- Tighter the cap is the more the O-ring is crushed/compressed
SRI PART NUMBER: 21021
![](https://cdn.shopify.com/s/files/1/0838/3732/1530/files/black-oring-profile.jpg)
Note Screw Head Height and O-Ring Colour
![oring-groove-style-old](https://cdn.shopify.com/s/files/1/0838/3732/1530/files/oring-groove-style-old.jpg)
Note O-Ring Groove Style
![Plastite Screw 48-2 Flat Head #4-20 x 3/8” Torx T8](https://cdn.shopify.com/s/files/1/0838/3732/1530/files/torx-old.jpg)
Plastite Screw 48-2 Flat Head #4-20 x 3/8” Torx T8