This is an adapter that converts LR44/SR44/PR44 batteries to the external shape of the mercury battery H-D (MR-9). Since LR44/SR44/PR44 are all the same size, you can use any of them. However, if you want to get the voltage closer to H-D (MR-9), use PR44. (※H-D: 1.35V, PR44: 1.4V) The following models have been confirmed to work: ・Canon FX ・Canon PELLIX ・Canon FP (FP meter) ・Canon FT ・Canon F-1 ・Canon FTb ・Canon TLb ・Canonnet QL17 ・Minolta SRT101 ・Nikomat FT ・Pentax SPF ・OLYMPUS OM-1 In addition to the above models, it can basically be used with any device that conducts electricity from the top and bottom of the battery. If you purchase multiple battery adapters currently on sale, including this product, we offer a combined discount. Please let us know the number of items you need in the comments, and we will provide a separate quote. ※This product will be shipped by regular mail and will not be delivered on weekends and holidays. If you are in a hurry, you can change to Yu-Packet by paying the difference in shipping costs, so please let us know in the comments. 【Terms of Transaction】 ・By purchasing this product, you are deemed to have agreed to all of the following: ・We are not responsible for any equipment failures or related damages caused by using this product. ・In some cases, we may refund the product price by canceling the transaction, but we will not provide any compensation exceeding the product price. ・We do not offer greetings at the beginning of the transaction. Please refrain from purchasing if you value communication. (※We will respond promptly to any questions.) ・Shipping will be completed within the number of days stated in the "Days until shipment" section of the product details. The number of days is calculated based on Mercari's standards. ・We cannot provide detailed shipping dates.