I near mint condition this slide dream machine made by National 
It is loaded with a pick up that work with an outside box that holds the battery 
Sounds absolutely gorgeous
Description by National :
The National Resophonic company presents the National Resophonic Triolian, featuring a steel body with walnut burst finish and a single cone. Available in original style 12 fret or 14 fret necks, these guitars produce a full, rich and lush vintage tone.
The National String Instrument Corporation patented and produced the first resonator instruments in 1927, responding to the constant need for more volume. The first instruments used three small cones – the classic Tricone design. In 1928, the single-cone design was introduced as a way to cut production costs, but this met great controversy within the company.
The National Triolian was originally introduced in late 1928 and built until 1938. Originally a wood-body guitar with a single resonator cone, in 1929 the Triolian was given a steel body. For much of the first year, a Bakelite neck was used but this miracle material turned out to be unstable and was replaced with maple.
In late 1934, the neck was changed to a 14-fret design, and to accomodate this, the body was ‘shortened’ – the scale length is the same at 25 inches, so there is no difference in string tension. This 14-fret body evokes an ‘OM’ (Orchestra Model) shape, while the original 12-fret model resembles a slope-shoulder dreadnought. Some players find that the larger body on the 12-fret model provides a slightly deeper tone and the 14-fret a little more ‘bark’.
The ‘Triolian’ name is a holdover from the name given the original prototypes, which had a trio of small resonators under one round coverplate. This proved too complex, and so the design, but not the name, was changed to the single cone we see now.
The ‘Duolian’ was a very similar instrument, but with less decoration, and an unbound mahogany neck.
The National Reso-Phonic company re-issued the steel body models in 2009, in both 12 and 14 fret designs. These are very high-quality instruments built to modern standards yet producing full, rich vintage tone. It *is* possible to have the best of both worlds!
Triolian Specifications 
Body:
Steel Body with F-Holes
Traditional ribbed sieve-hole coverplate, 14 inch wide lower bout.
Hand-finished in Vintage Style Walnut Burst
Neck:
Maple Neck
Rosewood Fingerboard
Grained Ivoroid Binding
Slotted Peghead
Mother of Pearl dot position markers
25 Inch Scale Length
1.875 inch nut width
Hand finished in Vintage Style Walnut Burst
Hardware:
9.5 inch hand-spun resonator cone and maple biscuit
National Brand open tuners
Hardshell Archtop National Case included