The open type (TR-70), closed type (TR-80), and semi-open type (TR-90) are the same variations found in the newly redesigned T-RP series headphones.  Veteran Fostex fans will recognize the distinctive Fostex-signature “slider bars,” which are also a nod to the design cues of the long-running T-RP series.  Each pair of TR series headphones comes with two sets of ear pads for customizability by the owner: a set of standard-thickness pads and a set of extra-thick ear pads.*  Each pair of TR series headphones also includes two different detachable, locking headphone cables: both a coiled cable and a straight one.

Specifications

TR-70(80)

Driver:    Dynamic, 40mm
Operation type:    Open
Impedance:    80 ohm 
Sensitivity:    93dB
Frequency Response:    5Hz – 35kHz
Maximum Input Power:    100mW
Weight:    298g
Cable:    Detachable 1/4” Stereo Phone (3m) Straight & Coiled
Ear Pads:    Normal Type & Thick Type
Accessories:    Carrying Bag, 1/4” to 3.5mm plug adapter - See more at: http://www.fostexinternational.com/docs/products/New_TR-Series.shtml#content-3-tab-tab