This is metric but advertised as imperial. It's tight, but you'll never be able to move the dowels. If you drill a 3/8 inch diameter hole, the anchor will not fit. To use this you will need metric drill bits and anchors which are hard to find in the US. I'm sure they work fine for metric dowels, but that's not what they advertise.
Premium Eapele 4X4 Wood Fence πͺ΅ Post Anchor Base: Secure Your Fence with Ease
8 Review
π© Hard-to-Find Quick Fastener 014973253790 - 4 Piece Set
7 Review
POWERTEC 4 Inch 20 2 Inch QTB1005 T Slot: A Revolutionary, High-Quality Power Tool Accessory!
8 Review
π© 5-Pack of M8x60mm Stainless Steel External Hex Expansion Bolts by Yasorn
10 Review