The head is made to fold down and the side blades to fold inwards over it. Opening it also opens the side blades automatically
This belongs to a rare group of folding spetums, of which seven other examples of closely similar construction are known to survive, respectively in the Hofjagd- und Leibrstkammer, Vienna (inv. no. A 458, originally in Schlo Ambras, near Innsbruck), Schlo Ambras (inv. no. A 457), the Real Armera, Madrid (inv. no. I 96), the Museo di Capodimonte, Naples (inv. no. CA 4423), the Bargello, Florence (inv. no. M 410), the Armeria Reale, Turin (inv. no. J 237), and the Muse de l'Arme, Paris (inv. no. K 202). The example at Madrid is illustrated in the Inventario Illuminado of 1544 of the Emperor Charles V's armoury, while the damascened decoration on the present example and those at Vienna and Ambras relates closely to that on Milanese parade-armour of the same period, for example on the work of the Negroli family, thus establishing the date and origins of the group. The Habsburg connections of the Madrid, Vienna and Ambras pieces and their high quality suggests that they may have been made for an imperial bodyguard, though Boccia has suggested that they were hunting weapons
An entry in the 1543 inventory of Francesco Gonzaga, Duke of Mantua for 'un spedo da forbeso che se desnoda' [a crab-claw spetum that can be dismounted], probably refers to a similar weapon.
The Rothschild example is the finest of the group (see A. Jubinal, La Armera Real...de Madrid, Paris, n.d., pl. 22; C. Buttin, 'La corsque', Bulletin Trimestrial de la Socit des Amis du Muse de l'Arme, no. 45, 1936, p. 84; L.G. Boccia, Nove Secoli di Armi da Caccia, Florence, 1967, fig. 44).