theres no delay for bass in the market.
Any delay can be used for bass as long as it doesnt rob you of the low end after processing
The circuit for delay doesnt distinguish between bass nor guitar or any other instrument. As long as you put a signal(be it people talking, bee buzzing or even air com hum) into the circuit, it will do its job, thats to delay, make signal repeat.
What some people do, is to use a larger cap in the input stage of the effect, to cater to bass signal frequency. But then, its prolly not necessary as well, to do so. Theres plenty of bassist using guitar effect and most importantly, as long as the low end is not compromised, a guitar effect even thou might alter the timbre of sound in some ways, it is not going to make a bass sounds like a guitar anytime.