Tefillin Batim of the Chazon Ish with the Straps

A pair of tefillin batim (leather boxes), made from thin leather (sheep or goat skin), with leather straps (without the parashiot – parchment scrolls inscribed with biblical passages) [Lithuania?, 1920s-1930s].
These tefillin batim where given by the Chazon Ish to his close disciple R. Avraham HaLevi Horowitz (author of Devar Halacha and Orchot Rabbenu), together with the parashiot. After a while, R. Avraham Horowitz ordered new batim (made of thick leather – cattle hide), and used them to house the parashiot of the Chazon Ish, while the batim of the Chazon Ish remained in his possession as a precious remembrance of the holy articles of the Chazon Ish.
R. Avraham refers to these tefillin several times in his book Orchot Rabbenu: "In Europe, and in the beginning of his stay in Eretz Israel, the Chazon donned tefillin fashioned from a single piece of thin hide. They were slightly larger than the tefillin which he later donned in Eretz Israel. Some time after he immigrated to Eretz Israel, the Chazon Ish ordered new tefillin batim made from thick leather, together with new parashiot (though I do not know how long after his arrival in Eretz Israel). In the last year of the Chazon Ish's life, my tefillin, which were also made from thin leather, got damaged, and for a period of time I would don the thick tefillin of the Chazon Ish after he finished praying. I later received from the Chazon Ish his pair of tefillin from Europe, made of thin leather, with the straps (these were very thick). I used them, and ordered new, thick batim, to which I transferred the parashiot from the tefillin of the Chazon Ish (these are not the parashiot photographed in the appendix of Orchot Rabbenu part I, the photographs are of the new parashiot of the Chazon Ish, from the thick batim). The thin batim of the Chazon Ish with the straps are still in my possession". (Orchot Rabbenu, III, p. 192; in the new edition, 2014, I, p. 39); "…the tefillin of the Chazon Ish, from a single piece of thin hide, which he donned in Europe and in his early days in Eretz Israel, and when he ordered here new parashiot, I received them (the old batim) with the scrolls, since that was the Chazon Ish's practice, when he ordered new batim, he also concurrently ordered new parashiot, since he didn't transfer parashiot from one set of batim to another" (Orchot Rabbenu, III, p. 195; in the new edition 2014, I, p. 81).
Enclosed are notes handwritten by R. Avraham Horowitz, stating: "Tefillin shel Rosh Chazon Ish"; "Tefillin shel Yad Chazon Ish"; "The straps of the Chazon Ish".
Tefillin batim (without parashiot): 40X40 mm. Size of base: approx. 74X48 mm. Including straps, in very worn condition.