SPY is currently at 263
Looking at the options 28 and 30 days, we see strikes 270, 270.5, 271, 271.5 or 265.5, 266, 266.5, 267 available.
Why isn't there something closer to ITM, like 262.5, 263, 263.5, etc. ? I just see 260 and 265 and nothing in between.