This deal is available again — 3rd Party Amazon sellers are discounting the Neewer 77mm ND100000 (16.5 Stop) Limited Neutral Density ND Filter by 20% to $31.59 with a coupon checkbox. This deal sold out quickly the first time, it’s now back (with an estimated ship date of early February). This is another decent photography filter for the upcoming total solar eclipse.
Other sizes are available, including 67mm, 72mm, and 82mm.