The Gibson J-45 is an acoustic guitar manufactured by Gibson. Widely regarded as Gibson's most famous and widely used acoustic model, it is often described as a "workhorse" guitar. The “J” designation refers to Gibson’s jumbo body style. Introduced in 1934, the jumbo represented Gibson’s response to the growing popularity of large-bodied flat-top acoustic guitars in the early 1930s, a market then largely defined by C. F. Martin & Company's dreadnought designs. The J-45 features a body depth of over 4 inches from endpin to neck heel and a rounded, "sloped-shoulder" outline that distinguishes it from the squarer upper bouts common to dreadnought-style guitars. While both designs occupy a similar segment of the acoustic guitar market, the J-45's proportions and construction give it a distinct tonal and visual identity.