Omega Jumbo Calatrava, ref. 2505-1, cal. 30 T2 in steel with box

A rare and fine Omega Jumbo Calatrava, ref. 2505-1, cal. 30 T2.
 
Stainless steel case, snap-on back, large 38.50mm diameter, flat wide bezel, sweeping downturned lugs.
Factory stampings to inner case back.
Case appears to have been gently polished in the past.
 
Original aged-white dial, printed silver arabic numerals and indexes, in worn condition.
Printed "Ω Omega" below 12 o'clock in black print and subsidiary seconds dial at 6 o'clock.
 
Original steel feuille hands.
 
Original Ω signed crown.
 
Original hesalite plexi crystal with crazing.
 
Omega Caliber Ω 30 T2 manual winding movement, unserviced and in good running order.
 
Brand new leather band with original Omega Ω signed Acier Inox tang buckle.
 
Original red velour fitted Omega Ω coffin box.
 
This is an extremely rare first release of the reference 2505, fitted with an Ω calibre 30 T2 movement. The reference 2505 is most commonly found with an Ω calibre 265/266 movement.