The Martin Tim O'Brian model features 00 body, Mahogany back and sides, and Adirondack top.

Full specs are s foloows:

MODEL 00-18 Tim O'Brien
CONSTRUCTION:Mahogany Blocks/Dovetail Neck Joint
BODY SIZE:00-14 Fret
TOP:Solid Adirondack Spruce
ROSETTE:Triple Ring
TOP BRACING PATTERN:Standard ''X'' Scalloped
TOP BRACES:Solid Adirondack Spruce 1/4''
BACK MATERIAL:Solid Genuine Mahogany
BACK PURFLING: Solid Madagascar Rosewood Strip
SIDE MATERIAL: Solid Genuine Mahogany
ENDPIECE:Black Boltaron
BINDING:Black Boltaron
TOP INLAY STYLE: Multiple Black/White Boltaron
NECK MATERIAL: Select Hardwood
NECK SHAPE: Rounded Full Thickness V w/ 30s Style Heel
NUT MATERIAL:Bone
HEADSTOCK:Solid/Square Taper
HEADPLATE:Solid Madagascar Rosewood /Large Golden Era Style
HEELCAP:Solid Black Ebony
FINGERBOARD MATERIAL: Solid Black Ebony
SCALE LENGTH: 25.4''
# OF FRETS CLEAR:14
# OF FRETS TOTAL:20
FINGERBOARD WIDTH AT NUT:1-3/4''
FINGERBOARD WIDTH AT 12TH FRET:2-1/4''
FINGERBOARD POSITION INLAYS:Diamonds & Squares - Long Pattern Golden Era
FINISH BACK & SIDES: Polished Gloss
FINISH TOP:Polished Gloss w/ Aging Toner
FINISH NECK:Satin
BRIDGE MATERIAL:Solid Black Ebony
BRIDGE STYLE:Belly
BRIDGE STRING SPACING:2-5/16''
SADDLE:16'' Radius/Compensated/Bone
TUNING MACHINES:Waverly Nickel w/ Oval Buttons
RECOMMENDED STRINGS:Martin Studio Performance Light Phosphor Bronze (MSP4100)
BRIDGE & END PINS: Solid Black Ebony w/ Abalone Pearl Dots
PICKGUARD:Tortoise Color
CASE:534 Geib style
INTERIOR LABEL:Personally Signed by Tim O'Brien, Numbered in Sequence Without Total.
ELECTRONICS:Optional
OTHER OPTIONS:Available left-handed at no additional charge