(Our apologies to Mr. Shakespeare.)
We've received questions regarding the lids for the SP-645.
First, you cannot use an SP-445 lid on an SP-645. This is because the two slots on the tabs won't lineup with the three film holders in the SP-645. So we modified the lids for the SP-645. You can see the differences here (SP-445 is on the left):
People have been concerned after noticing that the part number of the lid that came with their SP-645 says "SP-445". Here's the inside of 445 lid on top; 645 below:
Notice the "B" on the SP-645 lid. It was quicker (and cheaper) to just add a suffix to the part number rather than change the entire line of text. The modified lid (-2B) will work on either tank. Going forward, all SP-445s will come with the SP-645 lid.
Frankly, it never occurred to us that anyone would notice the part number...