$18
Maybe you have an Erlen rack from the time they came with one bolt? Lost the spares that came with the next round? of just need longer bolts?
This is a full set, 2@M5, 2@M6 1@M7 and 1@M8. this should cover the bases for "Most" seat posts that people using an Erlen rack would encounter.
For reference, some common posts and their bolts:
$120
UPDATE: 4/7/20 we have more on the way from Japan!, presale is open, inventory accurate...
$75 $95
This is the benchmark for one bolt posts....simple, elegant and just works. This is also...
$190 $195
Update: this is a preorder for our next batch from Japan expected to be here...