From DR:

TITE-FIT™ Electric Guitar Strings utilize a nickel-plated steel wrap wire wound on a round core wire to produce a fatter sound.  This classic construction makes TITE-FIT™ a great all-around string that works for a range of styles and genres, including Rock, Blues, Metal and Jazz.  The use of the finest core and wrap-wire materials ensure this classic design meets modern performance standards.

Who Are These For?

• Players who appreciate musicality and flexibility choose round core strings
• Guitarists looking for sweet mids, singing highs and a rich, full sound
• Musicians who prefer a smoother feeling string

Product Specs:

• Gauge: Heavy
• # of Strings: 6-String
• Core Wire: Round 
• Wrap Wire: Nickel-Plated Steel
• Total Length: 38"