diff --git a/btc-crawl.go b/btc-crawl.go
index 15cad86..d2aea25 100644
--- a/btc-crawl.go
+++ b/btc-crawl.go
@@ -1,8 +1,9 @@
+// TODO: Export to a reasonable format.
+// TODO: Use proper logger for logging.
 package main
 
 import (
 	"github.com/jessevdk/go-flags"
-	"log"
 )
 
 // Taken from: https://github.com/bitcoin/bitcoin/blob/89d72f3d9b6e7ef051ad1439f266b809f348229b/src/chainparams.cpp#L143
@@ -15,32 +16,30 @@ var defaultDnsSeeds = []string{
 	"bitseed.xf2.org",
 }
 
-// TODO: Unhardcode these:
-var userAgent string = "/btc-crawl:0.0.1"
-var lastBlock int32 = 0
-
 type Options struct {
-	Verbose []bool   `short:"v" long:"verbose" description:"Show verbose logging."`
-	Seed    []string `short:"s" long:"seed" description:"Override which seeds to use." default-mask:"<bitcoind DNS seeds>"`
+	Verbose     []bool   `short:"v" long:"verbose" description:"Show verbose logging."`
+	Seed        []string `short:"s" long:"seed" description:"Override which seeds to use." default-mask:"<bitcoin-core DNS seeds>"`
+	Concurrency int      `short:"c" long:"concurrency" description:"Maximum number of concurrent connections to open." default:"10"`
+	UserAgent   string   `short:"A" long:"user-agent" description:"Client name to advertise while crawling. Should be in format of '/name:x.y.z/'." default:"/btc-crawl:0.1.1/"`
 }
 
 func main() {
-	// TODO: Parse args.
 	options := Options{}
-	_, err := flags.Parse(&options)
+	parser := flags.NewParser(&options, flags.Default)
+
+	_, err := parser.Parse()
 	if err != nil {
-		log.Fatal(err)
+		// FIXME: Print on some specific errors? Seems Parse prints in most cases.
+		return
 	}
 
 	seedNodes := options.Seed
 
-	// TODO: Export to a reasonable format.
-	// TODO: Use proper logger for logging.
 	if len(seedNodes) == 0 {
 		seedNodes = GetSeedsFromDNS(defaultDnsSeeds)
 	}
 
-	client := NewClient(userAgent, lastBlock)
-	crawler := NewCrawler(client, seedNodes, 10)
+	client := NewClient(options.UserAgent)
+	crawler := NewCrawler(client, seedNodes, options.Concurrency)
 	crawler.Start()
 }
diff --git a/client.go b/client.go
index 2a5972f..21968d5 100644
--- a/client.go
+++ b/client.go
@@ -8,14 +8,12 @@ type Client struct {
 	btcnet    btcwire.BitcoinNet // Bitcoin Network
 	pver      uint32             // Protocl Version
 	userAgent string             // User Agent
-	lastBlock int32
 }
 
-func NewClient(userAgent string, lastBlock int32) *Client {
+func NewClient(userAgent string) *Client {
 	return &Client{
 		btcnet:    btcwire.MainNet,
 		pver:      btcwire.ProtocolVersion,
 		userAgent: userAgent,
-		lastBlock: lastBlock,
 	}
 }