diff --git a/lib/console/filter.rb b/lib/console/filter.rb
index a14908f..a109972 100644
--- a/lib/console/filter.rb
+++ b/lib/console/filter.rb
@@ -40,6 +40,10 @@ def self.[] **levels
 				const_set(:MINIMUM_LEVEL, minimum_level)
 				const_set(:MAXIMUM_LEVEL, maximum_level)
 				
+				# The default log level for instances of this filter class.
+				# Set to MINIMUM_LEVEL to allow all messages by default.
+				const_set(:DEFAULT_LEVEL, minimum_level)
+				
 				levels.each do |name, level|
 					const_set(name.to_s.upcase, level)
 					
@@ -206,6 +210,10 @@ def clear(subject)
 		
 		# Log a message with the given severity.
 		#
+		# If the severity is not defined in this filter's LEVELS (e.g., when chaining
+		# filters with different severity levels), the message is passed through to the
+		# output without filtering. This allows custom filters to be composed together.
+		#
 		# @parameter subject [Object] The subject of the log message.
 		# @parameter arguments [Array] The arguments to log.
 		# @parameter options [Hash] Additional options to pass to the output.
@@ -215,7 +223,8 @@ def call(subject, *arguments, **options, &block)
 			severity = options[:severity] || UNKNOWN
 			level = self.class::LEVELS[severity]
 			
-			if self.enabled?(subject, level)
+			# If the severity is unknown (level is nil), pass through to output without filtering:
+			if level.nil? || self.enabled?(subject, level)
 				@output.call(subject, *arguments, **options, &block)
 			end
 			
diff --git a/test/console/filter.rb b/test/console/filter.rb
index f2bc566..82227d0 100644
--- a/test/console/filter.rb
+++ b/test/console/filter.rb
@@ -114,4 +114,44 @@ def before
 			expect(result).to be_nil
 		end
 	end
+	
+	with "custom filter class" do
+		let(:custom_filter) {Console::Filter[noise: 0, stuff: 1, broken: 2]}
+		let(:custom_logger) {custom_filter.new(output)}
+		
+		it "can create a custom filter class" do
+			expect(custom_logger).to be_a(Console::Filter)
+		end
+		
+		it "has DEFAULT_LEVEL constant defined" do
+			expect(custom_filter::DEFAULT_LEVEL).to be_a(Integer)
+		end
+		
+		it "can log messages" do
+			custom_logger.broken(MySubject, "It's so janky")
+			expect(output).to be(:include?, "It's so janky")
+		end
+		
+		it "respects log levels" do
+			custom_logger.level = custom_filter::BROKEN
+			
+			custom_logger.noise(MySubject, "This is noise")
+			expect(output).to be(:empty?)
+			
+			custom_logger.broken(MySubject, "This is broken")
+			expect(output).to be(:include?, "This is broken")
+		end
+		
+		with "chained with another logger" do
+			let(:inner_logger) {Console::Logger.new(output)}
+			let(:chained_logger) {custom_filter.new(inner_logger, name: "Chained")}
+			
+			it "can log through chained loggers with different severities" do
+				# The custom logger has 'broken' severity which doesn't exist in the inner logger
+				# But it should pass through anyway
+				chained_logger.broken(MySubject, "It's so janky")
+				expect(output).to be(:include?, "It's so janky")
+			end
+		end
+	end
 end