These are large stirrups which probably date from the early twentieth century.
They have triangular sides with scalloped edges and suspension slots on top
They are made of a nickel alloy, possibly Alpacca and are not stamped with any maker's name
Dimensions : Width 4¾" (12cm), height 5" (12.8cm), depth of tread 4¼" (11cm)
Weight : 618g (1lb 5¾oz)
Ref : stirrup231