I don't make props, but honestly it does seem like it would be feasible to at least include or offer an obj. Maybe it's a pricing issue here? If they added it to their product it might bump the pricing higher according to the requirements here and if they just offer it on it's own they might have to price it higher than they feel is feasible for an obj due to the minimum pricing?

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I do not feel obliged to believe that the same God who has endowed us with sense, reason, and intellect has intended us to forgo their use.
-Galileo