diff --git a/NODES_on_Ethereum/relays.md b/NODES_on_Ethereum/relays.md
index 89b32f5..d524846 100644
--- a/NODES_on_Ethereum/relays.md
+++ b/NODES_on_Ethereum/relays.md
@@ -2,6 +2,12 @@
 
 <br>
 
+### tl; dr
+
+* relays are a bundle propagation service that receives bundles from searchers, simulate each txs, and forwards them to block producers.
+
+<br>
+
 ### mainnet
 
 <br>