P405, P410, P420, P450, P450-L, P4100 wideband probes introduced in 1956 with the 541/545 scopes. Do not confuse with the P400 probe for the 222/222PS/224 scopes.
(P405, P410, P420, P450, P450-L, P4100 wideband probes introduced in 1956 with the 541/545 scopes. Do not confuse with the P400 probe for the 222/222PS/224 scopes.)