Answer by taking a quote from the following article:

Clarence White (born Clarence Joseph LeBlanc; June 7, 1944 - July 14, 1973), was an American bluegrass and country guitarist and singer. He is best known as a member of the bluegrass ensemble the Kentucky Colonels and the rock band the Byrds, as well as for being a pioneer of the musical genre of country rock during the late 1960s. White also worked extensively as a session musician, appearing on recordings by the Everly Brothers, Joe Cocker, Ricky Nelson, Pat Boone, the Monkees, Randy Newman, Gene Clark, Linda Ronstadt, Arlo Guthrie, and Jackson Browne amongst others. Together with frequent collaborator Gene Parsons, he invented the B-Bender, a guitar accessory that enables a player to mechanically bend the B-string up a whole tone and emulate the sound of a pedal steel guitar.

Clarence White helped popularize the acoustic guitar as a lead instrument in bluegrass music, building on the work of guitarists such as Doc Watson. Prior to the advent of the more aggressive flatpicking style pioneered by guitarists like Watson and White, the guitar was strictly a rhythm instrument, save for a few exceptions (such as the occasional guitar track by banjoist Don Reno). Many of the most influential flatpickers of the 20th century cite White as a primary influence, including Dan Crary, Norman Blake, and Tony Rice. Rice owns and plays White's highly modified 1935 Martin D-28. David Grier and Russ Barenberg are two other acoustic guitarists who were heavily influenced by White's guitar work. White's bluegrass playing with the Kentucky Colonels was also a considerable influence on Jerry Garcia of the Grateful Dead, who traveled with the band during 1964.  On the electric side of the guitar spectrum, White was similarly influential. Together with fellow Byrds bandmember Gene Parsons, White invented the B-Bender device. This device raises the B-string (second string) of the guitar a whole step by the use of pulleys and levers attached to both the upper strap knob and the second string on the guitar. It is activated by pushing down on the neck, and produces a "pedal steel" type sound. Arlen Roth, heavily influenced by this style, did not at the time know that White and Parsons had invented a B-bender, so instead developed his own unique all-finger bending version of this technique. This was heavily documented in his ground-breaking book, "Nashville Guitar", all of his recordings, as well as his book "Masters of the Telecaster". Subsequently, his Telecaster sound became as notable as his bluegrass playing. Marty Stuart, another guitarist influenced by White's playing, now owns and regularly plays White's 1954 Fender Telecaster with the prototype B-Bender.  Music archivist and writer Alec Palao has called White "one of a handful of true greats amongst the instrumentalists of 20th century popular music", before adding that "the waves created by the guitarist's idiosyncratic style are still forming ripples within bluegrass, country and rock 'n' roll." In 2003, White was ranked No. 41 on Rolling Stone magazine's list of the 100 Greatest Guitarists of All Time. In 2010, guitar manufacturer Gibson ranked White at No. 42 on their Top 50 Guitarists of All Time list.

type of what?
is activated by pushing down on the neck, and produces a "pedal steel" type sound.