Fujitsu made F705i, 13.7mm thin to realize the hybrid structure with the adoption of the integrated circuit to address flat screen waterproof performance, a silicon rubber gaskets in the upper and lower case, of IPX5 and IPX7 standards. The standard was comparable to build a reliably waterproof performance by repeatedly submerged test immersion test, leak test conducted air and shipping condition pressure on the hydraulic test.

Its stainless steel bone body was further strengthened by first having metal into the mold to the bone body and from the closed mold resin infusion. Finally, the metal and cooling it to the bone became a case of a slim line thin rigid plastic waterproof phone.