The WAIN heavy duty connectors have casings with various protection grades such IP65 and IP68, fit for various circumstances. The stiff casing of standard IP65 can resist mechanical collision and pressing, which can satisfy the working environment in almost all factories. The stainless steel locking configuration and the casing with high protection grade IP68 comply with requirements of long-term ocean transportation which is exposed to salt, moisture and strong sunlight, or the requirements of tough environments such as construction sites and mines.