Responsa for Shevuot 86:9

לימא כתנאי המלוה את חבירו על המשכון ואבד המשכון ישבע ויטול את מעותיו דברי רבי אליעזר רבי עקיבא אומר יכול הוא שיאמר לו כלום הלויתני אלא על המשכון אבד המשכון אבדו מעותיך

but in the case of two handles we do not say this.<span class="x" onmousemove="('comment',' That he accepted each handle as security for 500 zuz, and if he loses one handle, he loses 500 zuz. For he did not specifically say that he accepted each handle as security for half the loan. We therefore say that both handles together are the pledge for the loan, and if he loses one handle, as long as the other is left, he may restore it to the borrower; and he deducts from the loan merely the value of the lost handle, and not 500 zuz.');">¹⁴</span> But R'Nahman Says, even in the case of two handles, if he lost one, he loses five hundred [zuz], if he lost [also] the other, he loses the whole [loan]; but in the case of a handle and a bar [of silver] do not say this.<span class="x" onmousemove="('comment',' That he accepted the silver bar as security for half the loan, for since a silver bar is sufficiently valuable to be accepted as part payment, the lender accepted it as a pledge only up to its value,');">¹⁵</span>

Maharach Or Zarua Responsa