The Oyster3 has an IP68 and IK07 rated housing. The device must be sealed carefully to achieve the IP68 rating.

Ensure that the clear silicon seal is in good condition, is lying flat, and is not fouled by any plastic debris or other material.

1. Close the housing, and gently squeeze it shut. Foam on the lid will compress against the batteries, holding them firmly in place.
    
2. Tighten the 6 screws to a uniform tightness. On the first assembly, the screws may be quite stiff.
    
3. The silicone seal is what is responsible for maintaining the integrity of the housing. So when sealing, we are looking for:
   1. Even pressure along all points of the seal
   2. A uniform gap between the housing lid and base (approx 1mm)
       
4. If you wish to replace the batteries and open the housing, be sure to check that the silicon seal is in good condition before closing the housing again.

Screw Part Numbers

The screws are a thermoplastic screw: 3.5mm x 12mm 

Posi-Pan Head (supplied with devices pre-Oct-22)

• BN82428
   
• If you are after a stainless steel variant, the product code to source is BN82429.

Torx Head (supplied with devices produced Oct-22 onwards)

• BN15858 M3.5x12 Pan Torx Thermoplastic screw – From Bossard.