5pcs TAIWAN 1-LED 1W 80-90LM 3000-3200K Warm White LED Bulb Set by QLPD. $19.78. The weld time should be controlled within 10 seconds. The optimum operating temperature is about 25¡æ. It is necessary to wear antistatic wrist strap during the operation. Thermal grease should be coated in the joint area. Each package includes 5 pieces.