Specialized products include the ESR, KTR, LTR, SFR, and SDR series of resistors. ESR resistors are anti-surge and protect against ESD. KTR resistors are high voltage up to 600V. LTR resistors have wide terminals which increase reliability and improve heat dissipation, as seen in the pictures on the bottom left. SFR resistors are sulfur resistant and are designed for industrial applications where sulfur is present.