Dunlop dna 18 gauge string reel the dunlop dna 18 gauge string reel is a premium mutli filament string that delivers power with enhanced durability this string features a unique pbt fibre coil which spirals round the cental core giving extra power and durability whilst still retaining feel and comfort specification bull construction dupont pa66 multi filament central core with pbt fibre coil bull gauge 118mm18 gauge bull profile fibres bonded with thermo elastic pu resin