Do you have long hair and often dries them?. You need a robust dryer with more power. The best will be a large model that can cope with even thick hair. Select one of the 3 temperatures and 2 speeds.
Remington Hot Air Styler HYDRA Lux Moisture Lock Ceramic Coated Barrel (REF 647)
Remington Hot Air Brush Rotating Airstyler Keratin Protect
Remington Pro Slim Hair Straightener Ceramic 230°C Black
Remington PRO 230°C Wet 2 Straight Hair Straightner Wet to Straight Bronze S7970
Remington Pro Ceramic Extra Digital Straighteners S5525 NEW FREE P&P
Remington Pro Ceramic Hair Straightener 45mm Wide Plates White